After Lion upgrade, I had to reinstall my python packages, and ran into problem installing PIL and pysqlite.
...
unable to execute gcc-4.2: No such file or directory
error: command 'gcc-4.2' failed with exit status 1
Turned out all I had to do was link up gcc-4.2, which was in /Developer/usr/bin
I added export PATH=$PATH:/Developer/usr/bin
to ~/.bash_profile