Haven't had much time to go through these yet .. but I wanted to make sure they got captured.
Here are some pages that have links to either compilers, compiler extensions or SDKs for the PS3 or Cell processor.
Linux devices - http://www.linuxdevices.com/news/NS5311012332.html
Sony Computer - http://cell.scei.co.jp/e_download.html
Game Tomorrow - http://gametomorrow.com/blog/index.php/2005/11/09/cell-sdk-now-available-for-download/
IBM - http://www-128.ibm.com/developerworks/power/cell/