Here's my experience upgrading from Stock ROM GB 2.3.6 to ICS 4.0.2
Briefly, here's the step;
1. Root your galaxy Note - For me, since I was on 2.3.6, I have to use Method 2 in my previous posting here
2. You should have ClockWorkMod app installed - look for CWM icon.
3. Reboot your Galaxy Note
4. Now, download the ROM package (in .zip format) from the link below and save it on your phone memory
Download ROM Here
This part is really tricky so pay attention :-)
5. Launch ClockWorkMod and select under Reboot the option "Reboot into ClockWorkMod Recovery"
6. Once it's reboot, navigate the menu to install a package ZIP file from phone disk. This is important - you can actually select your options using the touch screen, i.e. no need to use volume up and down buttons.
7. Once install, please reboot
8. After reboot, YOU WILL GET SOME "Unexpected Stop" messages for several application. DON'T DISPAIR. I got the same messages so just follow the steps below.
9. Launch the CMW again, similar to step (5) above
10. Wipe Dalvik cache via recovery (advance section)
11. Wipe data, factory reset again
12. Wipe cache partition
13. Reboot – all ok. – this time booted as if from new, rather than straight into homescreen
Thanks to RootGalaxyNote.com for the guide and instructions
BTW, here is a video on how to install a new ROM using CWM. This video could be confusing so let me know if you have any question.