I have heard alot about this topic; specialized compiles, hacking shells (hint, hint for all you phreakers) I personally don't have one since I have no connecting cable to my phone. If anyone has more info here is the place...some phones already run off of Linux. For more on that
http://www.pcworld.com/news/article/0,aid,108556,00.asp NEC is one of the companies looking into embedded linux. Here is some info on installing Linux on your mobil phone/cell
http://tuxmobil.org/phones_linux.html There's alot of info on the web...just do a google...I'm interested to see the feedback from this...I curious as to the feature set of linux on the cell.
Sorry that first link doesn't have anything on installing linux but it does have alot of stuff that may be of interest for any cell phone hacker. And currently Motorola is shipping their A760 to Asia with embedded Linux. One word: ebay.