There is a new site that I found which is called which lets you play some of the best open source games ever made. Transport Tycoon Deluxe is one of them, using the OpenTTD version of the game.

Authentic Transport Tycoon Deluxe!
The graphics, gameplay, music and sound effects works really nice. The site is tested with both Firefox and Google Chrome for OSX on a iMac i7 machine. Everything loads fast and I must say that I am impressed.

Check out OpenTTD site!

Not done Yet!
Including OpenTTD in browser, the site also got Dune II, X-Com and Caesar III on-line versions which is totally free to play also.

Thanks to Guryanov Aleksander for this site. May open source developers live long!