Robert_Charlton - 7:04 am on Jun 29, 2006 (gmt 0)

Depends also on the font. I like keeping Arial at 12px or larger. Verdana is wider and you could take it down to 11px or 10px... but I hate to use fixed px sizes really small because users can't resize them.

What is the smallest size that is allowed.

This, in my opinion, is completely the wrong way to look at this. It really is a usability issue, and that to me trumps everything.

I saw one site using around 8px to fit in more content.

If you're thinking that an 8px font is more usable than scrolling, you're not thinking very clearly. ;)