Siem Reap, which means Siam defeated, is the name of the small town just outside the main area of Angkor. There are over a thousand ruined jungle temples in the area, including Angkor Wat, the mother of all temples and a potential new Wonder of the World. You could spend weeks and weeks trying to see them all. I spent about a week there in February '07, and have no words to express the awesomeness of it. And photos... they really can't help, either. I nearly wept in frustration at not being able to capture it properly. Heh, I said wept.
Anyway, maybe at least the pictures will make you want to go there yourself, which I 100 % recommend. For a feeble attempt at a description of the place and my visit there, visit my blog.
And get ready for loads of pictures here of ruined temples and trees. Incredibly awesome trees. Cambodia has the best trees ever.