ROLLERCOASTER TYCOON 2

RCT2 is currently under development by Chris Sawyer and should be finished later this year (Around october) and this site has only just opened so so far. So far a fair few screenshots have been released but most sites have them

Rollercoaster Tycoon UK would be a good place to look

News so far indicates that there will be many new features and the game will havre an official license with Six Flags (a US theme park). The A.I will be improved stopping the people getting lost on large paved areas. Also coasters will have much more detail but the overall gameply will not be changed (a very good idea in my opinion)