I have Ubuntu 10.04 and the repository ppa:ubuntu-wine/ppa installed. When following your instructions (http://wiki.winehq.org/winetricks) to run winetricks I encountered a problem
Entering sh winetricks in a terminal window gave me the following error
Cannot find wineprefixcreate (wineprefixcreate)

With blind luck I tried entering just
winetricks
which worked, ie sh winetricks is not necessary. The error message was not informative and evidently is a hold over. It would help if this was stated on your wiki
Mark <><