Displayed transactions may not be correct!
You are running bitcoind 0.3.24.  This is a very old version that won't work properly on today's Bitcoin network. The latest version is 0.8.6.  

It appears that the Ubuntu maintainers have not updated the version of bitcoind in the standard 12.04 repository; so you'll have to get a current version from somewhere else.  The Ubuntu developers maintain a repository of their own for bitcoin, so you can install the latest version by doing:

sudo add-apt-repository ppa:bitcoin/bitcoin 
sudo apt-get update
sudo apt-get install bitcoind


You can also get these instructions from an "official" source by going to http://bitcoin.org/en/download and following the "Ubuntu (PPA)" link.

In answer to your other question, when you run bitcoind without arguments, it runs in the foreground and accepts commands on standard input (after a delay of a minute or two while starting).  You can exit it by typing stop.  You can also run it in the background by doing bitcoind -daemon, and then feed it commands by running bitcoind getinfo, etc.