It sounds like you have a good start. You can get lots of help here, but to give specific ideas we definitely need pictures. Also need to know your city or general area. Zone 8 covers a lot of ground and a great deal of differences around the state.

You need a photo host site like Photobucket, then you can put the link in the URL box below your post or copy and paste the html code right into your message. You can find the html code several ways, I use the "share" button on top of each photo.

Thanks...forgot about Photobucket...haven't used it in a while. Here is a link...hoping for some cheap, creative ideas...thanks all.
http://s496.photobucket.com/albums/rr324/msbeaniac/My%20yard/

Those are great oak trees and a good starting point. If you want to plant beds under the oak trees then lasagna gardening is your best bet. For inspiration I've attached a thread on the technique which shows Kathy/plantmaven's awesome success story.

I would add a level area for seating under the oaks. It can be gravel, mulch, or flat stones of some type. We find a lot of good stuff on craigslist. Leftovers from larger projects are often sold cheap or given away if you haul it off for them.

Start composting those oak leaves for a cheap source of soil to fill the beds. I buy a lot of plants on sale at Lowe's and looks for sales on special items at local nurseries.

This forum is a free source of inspiration. You can search or browse back through posts in the gallery. My favorite source of inspiration is commercial landscaping at businesses and shopping centers in my area. Take notes or pictures and post if you have questions.

Here is a link that might be useful: Lasagna gardening

Use the "HTML code"

Plant swaps are a great place to get started. The thing you want to find out first, strangely enough, is what NOT to plant. Some plants are aggressive enough to do damage to structures and swallow up an entire gardens. Along with that is plant identity to make sure of what you have. Many plants,especially vines and trees, sold at nurseries and garden centers are not a good choice near homes.
Joining here and a local garden club is a good way to do that. A local garden club can also show you first hand how certain plants behave in that area.
Welcome and good luck!

I've been reading quite a bit and getting really nervous about planting under the trees at all. Some posts even discourage lasagna planting. I certainly don't want my trees that are very old dying. But I do want some color and a pleasant area to sit and relax in. Now I'm more confused than ever.

You're exactly right about the trees. I've seen folks kill trees building beds around them. I've also known people who have built beds etc... and it didn't seem to harm the trees. Building a raised bed around an established tree will stress the trees. I can't say how much it will stress them or much shorter thier life will be.

That said, trees in the wild DO have an understory. This includes ground cover,vines shade tolerant shrubs. My advice is to add plants slowly ONE inch of soil a YEAR at a time. The first year put down an inch of good soil. Add drought tolerant,shade tolerant native flower SEEDS. When the flowers come up add a thin layer of mulch (1/2"). The next year add another inch of soil and more seeds. Do this one inch a year add soil (oh yeah 2ft from the trunk don't bury the root flare!) then shallow mulch until it's 5" deep. Then add native,drought tolerant,shade tolerant perenials here and there and allow them to spread naturally. Keep the soil away from the trunk. Keep it around 5-6 inches deep. Slowly add some very small native understory shrubs being careful not to disturb the tree's roots. Basically over like 5 years slowly add native drought tolerant (to prevent overwatering the trees), shade tolerant and native understory plants to mimic wild tree stands. If you plunk down a 5" layer of soil all at once and add a ton of plants and water you very well might stress the trees to death. Go slowly and give the trees time to adjust. Trees breathe throught the soil from trunk to drip line. It's smothering the oxygen and feeder roots with a huge pile of soil,plants and the water to get them established that kills the trees. By going slowly, one thin layer at a time, the tree can continue to breathe and develop more roots to compensate slowly to the new environment like they do in nature.

Very good explanation, PJ.

thanks for all the good advise. I'm still searching for ideas and have found some really gorgeous rock gardens, some of which even have tulips and stuff. I'm thinking if I put down rocks and slowly introduce some plants, I can also put those funning looking pots that are at an angle and some small 'garden junk totems or birdbaths' to make it look full until I can add more plants. The more I think about it the more I like it cuz I can put in an patio area in the center of the trees and some benches I can mosaic. Then I'd have to figure out what kind of soil or mulch or whatever (can you tell I'm new at this LOL) so I don't disturb the trees. I don't see any visible roots which I suppose is a good thing?

Sounds really cute msbean. Oak roots don't normally show.

Thanks...I'm getting punch drunk just looking at different designs. Wish I could just find a yard like mine LOL. I think I'm going to end up with drought tolerant plants...not too many...just enough and have some garden junk totems and fairies...or.... Just can't seem to find out if I need to put just gravel or rock down and if that will stress the trees or put some mulch underneath or... I think sparse would be better...don't want to take too much emphasis AWAY from the trees...just want to enhance them. Oh, and a small patio area in the middle of the trees with pavers or something with a small park bench and table. Oh...the ideas...now to do it without harming the existing landscape (such as it is).