I've seen this mentioned a few times on this forum and thought it would be an incredible experience. Can anyone provide more details on this and how to arrange such a trip?

Well, the only ballooning experience I'm acquainted in Angkor Wat is a different experience of what is considered ballooning: it didn't actually flew. Is just an up and down opportunity to take pictures of the Angkor Wat complex from the air. It costs 15 dollars.

Interesting Gilberto (the above poster), me and our spouses did the balloon ride at the same time. I don't recall that anyone else was on it when we were there. To add to what he said, it is a "tethered" balloon i.e. it is held with ropes. You go up about 300 feet and you do get a great view of the complex. You can see photos of the balloon (from a distance) as well as the view of Angkor Wat if you click on this link:

http://craigandjeane.photosite.com/Album1/?page=14

Thanks Gilberto and Craig for clarifying. Is the person in charge of the balloon just outside the temple complex so that I can arrange one of these photo opportunities?

It is not far from the complex. Your guide will know where it is.