Folks come for the Khmer Rouge history and a number of sights to that end can be found here. In town is the Ta Mok villa and on the Dangrek Escarpment, about ten kilometers to the north is Pol Pot's final home, his cremation site, and a few other items of recent Khmer Rouge history. The government is doing what it can to turn this place into a tourist attraction. Given that after ancient temples, the most popular tourist sites in Cambodia are Khmer Rouge related (Tuol Sleng, killing fields, etc), it's not such a crazy idea, but nonetheless the ambitions of the government have not produced the desired results and Anlong Veng still fails to attract very many visitors.
There are a couple of basic guesthouses and restaurants in town. The most interesting eatery would have to be the Choum No Tror Cheak Restaurant which offers an extensive menu of jungle critters whose sole qualification for landing on the menu is that they either walk, crawl, slither, swim, or fly - if they can catch it, you can eat it. Menu is in Khmer and Thai only. The restaurant is near Ta Mok's villa.
Set near the base of the Dangrek escarpment, and running around the edge of a man-made lake, Anlong Veng feels like the town Cambodia forgot about, and for a long time, that is just what it was -- it didn't really return to the government's fold till 1988.
Around 125km north of Siem Reap, this is one of the last redoubts of the Khmer Rouge, and the town was for years off limits. Today, close to an international border crossing and reached by a slowly improving road, the town is starting to develop and welcome the occasional backpacker that straggles into town.
Within the town itself there is precious little to do as the key attractions all sit atop the Dangrek range in the form of Pol Pot's grave and house along with Ta Mok's house -- the latter offers spectacular views as far as Phnom Kulen (on a very clear day).
The lake in town was caused by a small dam/spillway constructed under orders of Ta Mok. During construction they never bothered to clear all the trees from the area to be flooded and so the dead trees remain standing, creating a particularly eerie yet very photogenic scene.
Tourism is a pretty new concept here but there are a few motodops who speak a little English and will happily whiz you around to all the main sites -- the best way to see what Anlong Veng has to offer.
The area is also a popular area for dirt-bike tours (most of which run out of Siem Reap) mainly due to its rough-house roads and little-touristed feel.
If you're in a rush you could see everything Anlong Veng has to offer in a half day, but if you have time on your hands, you could easily spend day or two here.