Despite what I had said previously, I’m now not recommending installing solr & tomcat from ubuntu packages.
The version of solr that is provided by Ubuntu 9.10 is solr 1.2, which is over 2 years old. Installing directly from the solr .jar is likely better.
Tomcat was kind of pain in the ass anyway.
Thankfully Lucid will be getting Solr 1.4. More info on launchpad – https://bugs.launchpad.net/ubuntu/+source/solr/+bug/321889