It looks like you build Gentoo linux on the PS3 according to this link:
This link talks about offering pre-compiled binaries, compiled on PS3 (since compilation can be slow with limited memory).
According to PenguinPPC where I found the above link, they plan on hosting pre-compiled binaries for PS3 due to the limit memory of a PS3 (only 256 meg available to Linux). So might be a good link for the Gentoo lovers out there!
Here is a Slashdot article pointing to full install instructions as well.