My personal favorite DS game is now out for iPhone! I just installed it, and it's pretty good! Looks good, runs smooth, and has good controls. Basically everything that's in the PSP/DS version seems to be in here.
http://itunes.apple.com/us/app/grand-theft-auto-chinatown-wars/id344186162?mt=8
http://itunes.apple.com/us/app/grand-theft-auto-chinatown-wars/id344186162?mt=8