Here are some news regarding an OpenTTD port found by Dark Knight ez:

OpenTTD being the open-source remake of Transport Tycoon Deluxe, a game which some of you might remember from quite some time ago. It was a big hit on PC, having you create a nice economy by setting up transportation lines for goods and what-not in the world. Pure awesome.

Anyway, someone that goes by the nickname load*,8,1 is busy on porting OpenTTD to the DS, and has released a preview version. Lots of random crashes still, apparently, but they’ll be worked on and this shows you people just how perfect this game would be on the DS.

http://www.ds-scene.net/?s=viewtopic&nid=4933