10 gals are a pretty easy tank to start with the venture into planted tanks. You can easily find adaquate lighting, however, how much light you need depends on the plant species you want to keep, general rule of thumb is anywhere from 2-3 watts per gallon. Keep the powerfilter running, but if you keep the air pump running it will actually work against you. CO2 needs to spend time in the water column for plants to use it up so it needs to become dissolved into the water, by adding air into the water via the air pump, the oxygen being introduced is not allowing the CO2 to dissovle, and instead rushing it to the surface. With the powerfilter and plants you'll be getting enough dissolved oxygen into the water, so don't worry about that too much. Next is what to use for a substrate. Here's my suggestion, go down to home depot, and into the plants section, they should have Shultzs aquatic plant soil (5lb bag) pick up a bag of that its a nutrient filled soil pretty much the same as flourite. Then go over near the masonary stuff, and pick up a bag of playsand, your going to have more than enough sand as the bags are 50lbs. This might cost you around $8. When you start setting up the tank, the first thing that you want to put in, is the plant soil, put a generous layer on the bottom of at least an inch. Then wash 5-8 lbs of sand out to remove most of the silty debris, and put that over the plant soil. This helps keep the nutrients in the plant soil rather than clouding up the tank for a few days, I also reccomend sand because most fish species seem to like it much better than gravel, especially the corydoras cats as the sand doesn't damage their barbles and they can root around in it. Now you need a fertilizer, personally I like the liquid flourish line, so I would reccomend picking up a bottle of just plain old Flourish, it lasts quite a while and has seemed very effective in my tanks. For CO2 fertilization you can go quite a few roots, floursish makes a liquid carbon fertilizer but it gets kinda expensive, you could go out and buy a CO2 diffuser which can be fairly expensive, or you can make your own diffuser but its not as effective as one you can buy. Making one is fairly simple, get a 2 liter soda bottle, wash it out, put about 2 cups of sugar in it, then add about a 2 teaspoons of yeast. Take the bottle cap off, drill a hole in it big enough to fit a standard airline tubing inside, hot glue the airline to the cap so the end would extend into the bottle about 2 inches and make sure you have enough line at the other end to extend down to the bottom in your tank. Now simply fill the bottle about half full with water, stir the contents up a bit, put the cap back on securely, and attach the other end of the tube in your tank so the end is near the bottom. You will need to replace the sugar and yeast every so often.
That got a big longer winded than I was expecting, but I hope that helps you out, and if I missed anything or got anything mistaken, I'm sure someone else will jump in and help ya out.
Good Luck!
Brian