I've installed Organic Groups (on drupal 5.2) - how does a user create a new group? I couldn't find any block or menu that does this?

Also, how do i expose my taxonomy terms (2 level hierarchy with 6-8 terms each level) as tabs and sub-tabs ? Do i need to write a block, or is there a contributed module or menu i can install. I was trying to use Primary Menus for this, but i couldn't find the Secondary menu to provision with the 2nd level of terms.

Also, what's the best source to get drupal developers for customizing the site?

Any pointers would be very helpful
thanks
Kiran