Removing valve seals

I'm was gonna install some new camshafts, valve springs, and retainers, and in order to access the bottom retainer, you have to remove the valve seals. So naturally I'm gonna replace them like the Helm's manual says, but where can I find the tool for removing them, and most importantly, how can I keep the valves from falling into the cylinders, seeing as how I want to keep the head on during the job. I heard something about compressed air, is there a way to use an air compressor to fill the cylinders so the valves won't fall in? Thanks for any help.

as far as ther last question use the compression tester adapter and hook it up to an air line after you have it in the spark pulg hole

Thanks, I picked one up at Advance Auto Parts the other day, don't have to worry about it anymore though, since I bent a f**kin valve and have to take the head off.