www.needrom.comhas a collection of ROMs for this phone.
The things to remember are:
1. Always backup the existing stuff!
2. Ensure that phone battery is more than 70% and the computer laptop you are trying out the procedure from has sufficient backup power.
3. Ensure that whatever ROM files you get from the net are from reputed sources and are tested previously by multiple person. Flashing incompatible ROM will brick your phone. So big word of caution here.
4. Also don't forget to check MD5SUM/SHASUM of the file to ensure that your downloaded file is fine and not corrupted.
Flashing a custom ROM is dangerous if you are not careful!