Taking pedals off of a raleigh m20 help please!?

ive had by bike for 7 years and for about 4 of those years its been sitting there. i love to go trail riding but since i live in the city i use my mongoose hoop d alot more. so everything has rusted out on my raleigh. including the sprockets and such. and i cant take the pedals off to get the sprocket off. ive taken the nuts of the bolts on each side but they dont seem to pull off like on any other bike. so i was wondering if im not doing something im supposed to or is it just rusted on or what?

You need a "crank removal tool". You can get one from "park tools". It screws into the threads and has a wrenchable cylinder that pushes the crank off of the bottom bracket.

You need a LOT of force to take off pedals, especially those which have rusted into the crank arms. Get a massive wrench, hold the other pedal and put your whole body weight into it. Remember on (I think) the left-hand pedal, to take it off you have to turn the wrench clockwise (opposite the the direction would would normally unscrew thing) this is because if the thread was normal, the pedal would naturally unscrew as you rode along...which you really don't want happening.

I can't picture what you're trying to do. Why would you want to remove the pedals to change the sprocket? Possibly it's a matter of terminology and, as a previous reply suggested, you're trying to remove the cranks - though I couldn't imagine why this would be necessary either. If you're wanting to change the chainwheel, depending on the design, that can also often be done without removing the pedals. In any case, he's told you what to do to remove the cranks. If it's really the pedals you want to take off, remember, as you've also been told, that the right-hand pedal has an ordinary right-hand thread, but the left-hand pedal has a left-hand thread.
I would suggest you take the bike to a bike shop so that they can have a look at what's going on.
Alternately, get your terms sorted out and send in the question again describing clearly exactly what it is you're trying to do. There are plenty of very knowledgeable guys here who will gladly advise you, but you have to explain properly what you want.