Need a GBA rom cartridge

What would be the easiest/best one to get? And I'm in the UK - where would I order one from? Thank you!

It depends on what DS flash cart you have. Your safest bet would be an EZ 3in1 V GBA flash cart-order it from DealExtreme, I have ordered from them many different times and they are consistently reliable.
miros

DealExtreme is an American company so not much use if you're in the UK. I use these guys http://techwizad.com/index1.html but sadly they have no EZ 3in1's in stock at the moment.

Guys he was asking for a GBA flash cart, not a DS one.

http://www.gbatemp.net/index.php?dynamic=8 Reviews :)