Rom help?

Hey guys, I'm fairly new to this whole thing so please bear with me. I own a DS lite and I'm familiar with R4's that work on DS lites. However I'm keen on finding out a few things about the newer DS'. Will the roms I currently have work on DSi/DSiXL? I know that I'll need a different type cartridge but what about the actual rom? Also which is the best cartridge to use on a DSi/DSiXL?
Thank you!

So NO ONE on a rom forum can answer a simple question? Right then.

Replying to #2

maybe people have other things to do instead of repeating themselves since some people (like you) are lazy to look for the answer on this forum. but all you need is a flashcart that works with dsi/xl. best ones are supercard dstwo and acekard 2i