As far as tourist sights go, there aren't many in Saigon. Its a very interesting city, but given the wars, its relatively new and lacking in historical sights. The French colonial architecture is prevalent and constitutes the majority of Saigon sights.

City Hall. Classic French style. You don't actually go in the building, so this is purely an architectural sight. It was once the French colonial headquarters at the turn of the 20th century.

Ho Chi Minh. This statue is outside of City Hall in a square in the center of the city. Ho Chi Minh liked to be known as Uncle to the locals. Thus in this statue he is playing with little children. The square is also excellent for scooter/traffic watching as it can get hairy on the roads around the square.

Saigon Notre Dame Basilica. This is a Catholic cathedral in downtown Saigon, constructed between 1863-1880 -- during the French colonial occupation. The statue out front is of Saint Mary.

The colonial post office. Still a post office today, it speaks to the lack of tourist sights in Saigon as it was packed with tourists. I mean really, its an impressive building, there are gift shops and of course, its a post office -- but who really flies half way around the world to see a post office??? Oh yeah, we did. Silly Jason and Meghan.
(Actually it was really pretty and I imagine exactly how it was when the Frech built it -- minus the gift shops.)