The most popular ROM right now is CyanogenMod 7, which is based off AOSP Gingerbread. Many people are awaiting CM9 which will be based off AOSP Ice Cream Sandwich. You might be wondering why it’s called CM9 and not CM4 since ICS is Android 4.0. CM naming is based on how many versions of Android there have been. Although ICS is Android 4.0 it’s the 9th release. There is no CM8 because Honeycomb was never open sourced.
Anyway, there is a CM9 ROM for the Nexus S that is in early alpha stage. Right now most every essential function is working.There are a few kinks to iron out with video playback and MMS, but other than it’s fine to be your daily driver. The ROM was built by Koush, who Android enthusiasts might know from ROM Manager. If you’re just itching to get CM9 on your Nexus S follow the XDA link below. We also have a video of CM9 running on a Nexus S below.