This script
http://www.fship.com/demos/rpm2targz, will convert an RPM into a simple tar.gz archive, which you can then extract into which ever directory you wish.
[code]localhost:~ $ wget http://www.fship.com/demos/rpm2targz
localhost:~ $ chmod u+x rpm2targz
localhost:~ $ ./rpm2targz file.rpm
localhost:~ $ tar xzvf file.tar.gz