I have several DS and GBA games that I would like to back up on a flashcard (specifically my huge pokemon game collection) and I was wondering what would be the best flashcard to buy for this. I would also like to experiment with maybe DS linux (I'm a huge fan of linux) or some other PDA style applications.

How much would a flash card setup (hopefully forwards compatible with the DSi) cost me? And how exactly do I use it?

Also, is a flashcard and a DS lite in any way comparable to using a PSP and a memory stick for legit homebrew gaming?

Thanks for the advice, everyone.