How do I make Acrobat 9 Pro my default pdf app?

I used to have this set until an upgrade of the OS or ... when I installed Acrobat 9 Pro??

I am still running OS 10.5.8, though will upgrade to SL soon.

Anyway, I can't figure out how to make Acrobat my default instead of Preview when I:

1) open a pdf file on the web, or

2) double click on a generic pdf (such as one sent as an email attachment), or

3) export to Acrobat from Apple's Pages

Any suggestions would be REALLY appreciated!

Thanks