Yes it does. I started with Poser 7 on Tiger, then upgraded to Snow Leopard. Poser 7 still works fine for me. It's a long time since I used it, so I just opened it up and did a few renders, ran a few Python scripts, just to make sure!
As far as I am aware there were no technical issues with Snow Leopard and Poser 7. I would recommend upgrading to the latest Poser 7 Service Release, available off the SM web site. The SRs contain some significant performance and quality improvements, as well as many bug fixes.

Edited to add: you only need to apply the latest SR, which is SR3. Available from:
Poser Updates

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)