How to root Vodafone 858 (froyo) / Huawei u8160
Apparently the recommended tool would be SuperOneClick. It seems that this is malware infested though. Apparently most sites took down their downloads, so maybe it is indeed bad.  I tried to find another tool and found this:
http://www.kingoapp.com/android-root.htm

I tested it with an online scanner and it got 6 hits out of 65, so use at your own risk. However I tried to find information about it and it seems to be ok and the alarams are claimed to be false positives. I used it successfully to root my VF 858, so it works. However if somebody finds out that this is indeed infested with malware then remove this answer or drop a note.

Usage is pretty simple as you just have to connect your device, enable USB debugging and then press the buttons in the Wizard.