I assume that you are from stock kernel and not rooted.
1. Download CM7.1 stable version
2. Backup you current application to APK file format and copy to your PC. You need it after CM7 installation completed. How to backup file to APK? Click here
How to install CM7.1?
1. Root your device and install ClockworkMod Recovery.
If you do not know how to root your current ROM. Try steps inside two links below. It will ROOT and install ClockworkMod Recovery by default.
2. Copy "update-cm-7.1.0-GalaxyS-signed.zip" into you phone SD Card. Rename it to "update.zip"
3. Reboot into Recovery using 3-button-combo (Volume Up+Home+Power button)
4. Do a backup! Best practise
5. WIPE (wipe data/factory reset + wipe cache partition + Dalvik)
6. Install "update.zip" from internal sdcard using Recovery Mode
7. DONE. Sit back and relax
- You will have clean CyanogenMod 7.1. Very FAST!
- No Google or Samsung apps. Need to download and install separately
- Do not use new market. Download Old Market and copy into you phone SD Card.
- Remove "marketupdater.apk" and "vending.apk" using DarkyROM tool. Install this first.
You can't download google apps from old market? You did not see most of the google apps? I will show you how to download it after the break... coming soon