Definitely hire a licensed structural engineer to take a look. We are in the design phase of our kitchen remodel and plan to take down a wall to open the kitchen up to the family room. Our design/build kitchen company has scheduled a structural engineer to examine the wall next week. They said the structural engineer may say that either nothing needs to be done or a support column many need to be placed there. If we need a support column we'll have to make it a decorative one and place it on the end of our kitchen peninsula and have it go through the cabinets all the way down into the basement. We are also using the engineer to tell us if we can catherdral our family room ceiling. It is an extra cost of $600 - 800, but I will sleep better at night knowing that the construction work is being done properly. Good luck.

On costs: I assume you're wanting to know generally how much things cost so you can make a decision about whether you can afford this. This advice is just ballpark general, not meant to give you a solid number, but an idea. Are you thinking of a contractor to take care of demo, electrical, plumbing, cabinet installation, painting, and possibly flooring? If you need someone to remove a load bearing wall and add in a supporting header, you'll almost surely need a pro. The advantage of a (good) contractor is that things will get done on a reasonable time schedule and done right (cross your fingers). He or she will also pull permits and call the permit people for inspections (if someone says he "doesn't do" permits - run). Using a contractor will almost double your budget, but has obvious benefits. If you DIY, you save money, but you also extend your timeline and rely on your ability to do the labor. You'll probably still need to find a plumber, electrician, and maybe a cabinet installer and flooring person. If that's a load bearing wall, you'll probably need a carpenter and a drywall person. You still need permits, so you have to go down to the city and figure out how that works. DIY should only be undertaken if you're good with tools, good with measuring, have patience and an even temper, and know what lies beyond your skill set. If you work full time, plan on this project taking a goodly amount of time and stress. Do you need new appliances? The first time we did this we only needed a new fridge. We're pretty middle of the road on our appliance tastes and budget, so a refrigerator we were really pleased with was around $1200 on sale. More recently we needed everything, so around $1300 for new fridge, $1100 for an induction range, and $850 for a Bosch dishwasher (worth it!) - we try to hit sales. Cabinets come in a big price range. At the least expensive end you can go with Ikea cabinets, which people here think highly of. Prices I've heard range from $4000-$8000 for Ikea. Along the same lines you can check out Barker and Scherrs online for doors for Ikea boxes or the whole cabinet. Both come with good recommendations from GWers. After that, you can find decent to fabulous cabinets fully assembled that will run from around $10,000 to $60,000. Ours for a small to medium-small kitchen ran about $14,000 and we'd do it again even if we had $35,000 to spend if we wanted to. Other stuff: Sinks can range from $150 for something simple to $2000 for fancy-schmancy. Figure at least $400 for a main sink and possibly some more for a cleanup sink. Faucets can range from $100-$1200 or more. Range hoods, microwaves, backsplash tile, countertops (at least $5000 unless you do laminate), pendants for over the island, and general and undercabinet lighting (always more than you think) all add up. If I had to guess based on your current kitchen and what you want to do, I'd guess you're looking at a minimum of $35,000 if you spend very carefully. $50,000 wouldn't be unreasonable.

20 feet is quite a span...the wall probably does play a structural role. Look in the attic...does each of the ceiling joists span the entire 20-foot width? If the ends of ceiling joists are resting on the wall, it is positively is a structural (load-bearing) wall. In any case, today's code regarding a 20' open span would call for joists larger than 2x6's or 2x8's. If that's what you have, yes, you need larger joists and it probably isn't financially feasible to remove the wall. If you still think that you can remove the wall, bring in a structural engineer before attempting anything and make sure any work is done to your city's building code.

Be sure to frame out the doorway with a header and jack studs. It distributes the weight. Sawzall the studs. If you need help, hire someone.