If you would like to customize your Sony Ericsson Xperia Play, overclock it, or just for a change here is a ROM list, just to make it clear I want to tell you that I will be writing tutorials later for easy Xperia Play Rooting, because the process needs root access, sometimes recovery flashed, and other times unlocking the bootloader which will void your warranty.
Here is How to Root Xperia play without unlocking bootloaderand How to get Recovery on Xperia play to flash Custom Roms without Unlocking Bootloader
The most realable custom rom for the Xperia play now is Cyanogenmod, everything else seems a little bit of buggy, anyway I would love it if you comment and tell me about me if there is other ROMS and which ones you like, for me I am kinda sticking to stock rom and modified it to my needs, and only flashed a new Kernel that is based on the stock kernel anyway with some mods.
so here we start.
1. Ice cream sandwich for Xperia play Cyanogenmod 9 click to visit my post about it
2. Cyanogenmod 7
Lets start with the famous Cyanogenmod make sure to download the latest stable version, personally it's the coolest ROM but you will miss things like Xperia Play gaming app, you can get it later by backing it up before flashing, anyway I advice you to do a Nand backup via recovery before flashing, there was an issue with touch pads but now it works fine, and you need also to flash a custom kernel which is FreeXperia.
anyway here is the ROM download page
and from here is a tutorial on how to install Cyanogenmod on Xperia play
3.MIUI Port for Xperia play
Before you procced with this ROM I wanna tell you that at the time I am writing this post the bluetooth and touchpads still don't work on this port, it's an effort of XDA forum members and not an official rom from MIUI, but overall this have the best looks :)
also you can make your own MIUI using speed porting tool, read here.
4. ICX or Ice Cream Xperia Missing the sandwich tho
WARNING:This is for testing, it boots it works but there is lot of stuff that doesn't actually work
Can't mount usb
and a lot more
But anyway go here and check if the developer updated it:
Read more and download
Don't forget to comment or ask any questions, I will be glad to answer :)