I have compared all currently available multi language plugins available on wordpress.org and have picked the three most promising.
I'd lke to get some feedback in case you have used or are still using one of them. I am currently also reading through the forums to check what problems others ran into with them. If I can't make up my mind, I might give them all a try and post again here afterwards.
These are the three I found to have the most features:
Please don't simply suggest another plugin, first check if its features are comparable to these plugins!