After the arrival of nightlies for Galaxy Nexus, Nexus S and Motorola Xoom, CyanogenMOD team has started releasing CM9 nightlies for more Android devices – Samsung Galaxy S II, Asus Eee Pad Transformer TF101 and Transformer Prime TF201. On the other hand, Galaxy Tab 10.1 (T-Mobile, I/O Edition & Wi-Fi only version) have got the official CM9 snapshot builds.
These nightlies can now be grabbed from http://download.cyanogenmod.com/. The code-names for Tab 10.1 WiFi | I/O vesion is p4wifi and T-Mobile version is p4tmo, others would be easily identifiable.

Please help me out with how to install this perticular nightly build for my Galaxy S2.. Are the following steps correct??
1) wipe data and factory reset
2) wipe cache partition
3) wipe dalvik cache
4) wipe battery stats
5) install the zip file
Or is it necessary to install the very first nightly build (nightly 1) first and then install this latest one?? Please reply.. I am confused..
Go through 1st and 2nd posts on this thoroughly, and you’ll be fine.
http://forum.xda-developers.com/showthread.php?p=20671183
does it requires root to make it work on sgs2?