Hi Tobias, in version 2.5 or version 3 there is a new "Flow" command which is the easiest way to do that.
The easiest way is probably to use "curve-to-curve" flow - that's where you will have a line below the text which will be the base curve and the target curve will be arc or a circle curves that has the same radius as your cylinder, see here for an example of that: http://moi3d.com/forum/index.php?webtag=MOI&msg=5097.2
For mapping directly onto a cylinder you can put a plane underneath the text and then use surface-to-surface Flow. For that case the location where you pick on each surface is important, see here for some previous examples:
