I'm wondering if there is a way to get the member count correct in the block. It appears that the block always has 1 more than the one visible in the forums (I also noticed the block matches the statistics module).
Another Question: Would it be possible to make it that if a mod or admin is logged into the site, the block would make their user names as another color? Just like the forum footer where the mods are green and the admins are orange.
Thanks in advance.

Good questions! waits for answers

I have answer for your first question.

I had same problem, one more member was displayed in the visitor info block.

The reason is that somewhere in the block the sql command count the anonymous user too while in the phpbb it will not be count.

I was using block-User_Info.php and after switching to
block-Site_Visitors.php problem was corrected.

you can d/l block-Site_Visitors.php from this site.

Wow thanks! I'm actually surprised I got a response here.
I ended up deleting the anonymous user (I hope its not a problem) and it fixed it for me.

Anyone happen to know how to make the names come up in different colors?

Those names come up different colors in the forums because of the css associated with the forum. You might be able to do it in the block, but I think you'd have to add an extra sql query to it, that would pull the mod info from the associated table the same as for the forum. You would probably have to add the same color association to the style.css for your theme too.