./winetricks vcrun2008 vcrun2005 allfonts d3dx9 win7
If you still have audio issues after doing this and your distro uses Pulse Audio (Ubuntu does) install Wine 1.2 that has been built with pulse audio support with the following commands in terminal:
sudo add-apt-repository ppa:c-korn/ppa
sudo apt-get update && sudo apt-get upgrade
If you have audio issues under Crossover you can open your Starcraft 2 bottle's WineCFG, select the audio tab, and set hardware acceleration from full to emulated.
Note some drives may use /dev/sr0 (or other mount points) instead if /dev/cdrom. If you are having issues getting it working scroll through the comments for some good tips - if you are still unable to get it working after that, make a comment of your own :)
Also - if you are attempting to get the game running with an ATI card, it was suggested in the comments that making it run under a virtual desktop allows it to run on some systems it otherwise fails to work on.