While LG will most likely not be upgrading the low-end LG Optimus One P500 to Ice Cream Sandwich Android 4.0.4, we already have a port of CyanogenMod 9 for the P500. The development is currently in Beta stage with most of the things working. 
What doesn’t work:
- Wi-Fi tethering
- USB tethering
- Offline charging
- FM Radio: not implemented in CM yet
- Camcorder
HOW TO INSTALL
- Download the ROM from here and GAPPS from here.
- Boot into recovery.
- Wipe data/factory reset, format /system, format /boot, Wipe Dalvik Cache.
- Flash ROM.
- Reboot
- Go to recovery again, flash GAPPS and reboot.
There you have ICS 4.0.4 / CM 9 on your LG P500. 
P.S. – You need to be using new baseband.
Hi, Is DarkTremor fully functuonally ??
Yes DarkTremor works. However I would recommend using Link2SD.
Installed and happy… i have ICS 4.0.3 / CM 9 !!
Thank You !
how can i get new base band iam on mike cm7 6.5.8 old baseband .please give me a guide.i want new baseband without going to V20g that is 2.3.3 .can i get new base band from mike cm7 6.5.8
Hey Nikhil..Yes you can do that. Just follow the below guide.
http://www.manast.com/2012/01/23/how-to-upgrade-to-new-baseband-on-lg-optimus-one-p500/
I tried installing and theirs no service! someone help
Upgrade to the V20g baseband.
Market wont work. What should i do?
Tristan, Market works on the latest Beta i.e. Beta 3.
Hi guys, I have LG Optimus P500 and would want to root the phone, but I have no idea how to go about it. Can somebody help me understand what is the best way to do that. My major problem is that my phone does not have enough internal memory as it is blocked by a lot of bloatware that came with the phone.
guys, i have no idea in doing all of that?
Guys i install CyanogenMod 9 / Android 4.0.3 ICS on mobile LG Optimus One P503 but no network services
Guys i install CyanogenMod 9 / Android 4.0.3 ICS on mobile LG Optimus One P503 but no network services, camera
I really like my android 4.0.3 but youtube doesnt work and also put some radio on it. Looking forward for the stable version.
i prefer to wait the finaly rom ics for our lg p500
I tried it its very gud but vedioes won’t play neither YouTube.lags a bit waiting for a stable version atleast nightly.can anyone tell wen they are going to release..
Hi,,i have instaled that rom on my brothers lg optimus one yesterday and i flashed it from stock 2.3.3 but wifi is not working (i think it isnt the problem of baseband) can you help me what to do???
Wipe everything and flash again. See if the problem is resolved. Wi-Fi works fine for me.
NO it is not helping,,,! I have flashed 3 different ICS roms and one is CM9! NOTHING WIFI is not working(((
WiFi is working fine for me on all the ICS ROM’s available for Optimus One.
Does Wi-Fi work for you on GB?
Rom works really well. My only problem is the constant stutter in video playback. You can’t watch youtube in HD, or play any other videos you find online without severe choppiness. Any chance a fix is coming?
i have flash this rom its very good but i want a working fm for this could u pls help me with same
hai i am using this rom its working great please do something in usb therthing..
USB Tethering is a bug that will be worked on. For wireless tethering try this:
https://play.google.com/store/apps/details?id=android.tether