Dear All:
Accidentally, today I just followed a tutorial about how to install Tomcat6 on Ubuntu(my version 8.04). right now I depoly Geoserver 1.7 RC2 on tomcat. Everything are work fine. I dont think there is any problem with 1.7 RC2.
The installation of Tomcat 6 tutorial is
http://www.howtogeek.com/howto/linux/installing-tomcat-6-on-ubuntu/
All the best
Xiaoyu