Thanks for those replies.
pmcizhere: I'll give PocketGBA another go. I tried it a few weeks ago and the roms didn't work. But I'll try again with the games you suggest and see how it goes. I've only got an X5 so maybe that's too slow.
Frannyman: Thanks for your suggestions. Snoopy Tennis sounds like fun
. And I'll try the others especially Dragon Warrior I and II and Survival Kids .
What do people think of Harvest Moon? I read that it was good but I think you're a farmer which sounds really boring.
Thanks again for your replies and it looks like I'll have to buy a bigger card :)
david