If you want to run GBA games, the DSLinker is not a good option. Anyways, we have a review here:
http://www.emuparadise.org/reviews/DSLinker/
You'll find he best compatibility for GBA games in the slot2 flash carts. I have a M3 Perfect Micro SD and it works great for both GBA & NDS games. If you decide you want a slot2 solution, you'll need a passkey and a SD/CF card. That's all you need, and the compatibility is simply great, you can check
it for yourself.
Another good option but without GBA compatibility since it's a slot1 card is the R4, some of our members already have it and they've shared their experience with us:
http://www.epforums.org/my-experienc...067/index.html
And yeah, if there's enough interest we could have a sticky. If I have some time I'll try to post some useful links later.