if you are using an original cartridge, then i dont think you can. if you are using an m3 simply or anything equivalent to that, you just plug it into your card reader and transfer it. kcajblue was saying that there is not site where you can use to copy your pokesave from an original cartridge to you computer.
nope. i meant there is no official site for pokesav. and if you want to download it. just google it and youll find a download easy.
well first off, i believe you are talking about an original pokemon ds game right? you cannot put any saves or write any saves onto that cartridge. m3 simply is a ds cartridge that allows you to play backups of all your ds games in one place, so you dont need to keep switching roms.
you buy one. dealextreme.com has one of the cheapest ones but it takes a while to get here. there are other cartirdges such as the r4 (which is the same thing as the m3 simply just another name, the g6, and ezflash. i suggest you search around the forums to find the one you are willing to buy