After some research I found out, that the repo provides the old version 2.6 of the MonoDevelop IDE, but as there is already the latest version published I want to know whether someone knows how I can install it (there is no package out for Ubuntu 11.10) without messing up my current system.
You can remove the version of monodevelop installed through Ubuntu's software sources, download the source code archive for monodevelop 2.8 upstream (http://monodevelop.com/Download), and build and install the source manually. See https://help.ubuntu.com/community/CompilingEasyHowTo for general advice on building software from source.
I was also looking around, and I found a ppa that might interest you if you have not already found a solution:
I just installed it and it seems to be working alongside with 2.6 with no issues. Cheers
I came across this thread looking for this exact issue. While this was of some help, I found this tutorial to be a great resource as well. Just wanted to share.