how to install PDT 2.0 in Ubuntu 8.04 the simple way
1. uninstall eclipse 3.2 which comes from the Ubuntu repositories. Don’t worry about the files that you already have as they will be safe.
2. download latest eclipse (ganymede at this time 3.4). Choose Eclipse Classic version.
3. unzip and put somewhere in the system.
4. download PDT 2.0.0 and unzip.
5. go to eclipse/help/software updates/available software/ add site / local and point to the unziped PDT folder
6. install and restart