Using Apples Time Machine to back up my work macbook has been on my todo-list for quite a while. This was pretty easy in the pre-lion days and only required a samba or nfs-server available to the mac. Apple has changed this - now it takes an appletalk share to do the backup. I'm sure that the decision to no longer support other protocols has been made only on technical grounds and not to increase sales of apples own time-capsule.
Here are the steps to get things to work: