I don't know how I missed this but I just discovered that maven2 is available in the current unstable release (Hardy Heron).
So, happy Hardy Heron users, if you want to use maven2, installation can be pretty straightforward:
$ sudo apt-get install maven2
Et voilà! After a few seconds and the download of a bunch of new dependencies and files, maven should be installed and working correctly. This can be verified using the following command:
$ mvn --version
Which should should print something similar (at the time I'm writing this) to:
Maven version: 2.0.8
Java version: 1.6.0_06
OS name: "linux" version: "2.6.24-12-generic" arch: "i386" Family: "unix"
It's not that it's complicated to install maven manually and I was happy with my current setup and will keep it for various reasons (mostly because I'm using 2.1-SNAPSHOT) but a well integrated package is always nice and helps: no ENV variable to set up, no PATH to modify...
Actually, this is precisely one of the reason I really like Ubuntu : Apache, Java, Ruby, Python, Scala, Groovy, PHP, Maven, Ant, MySQL, PostgreSQL, Tomcat, Glassfish, Subversion,... you need something? just "sudo apt-get install" it.
Ubuntu is definitively a great development environment!
Note: Gutsy Gibbon users can try the backports available in Matti Lindell's Personal Package Archive as mentioned in this comment or wait for the release of Ubuntu 8.04 which shouldn't be a big issue as it will occur in a few days now.