Requirement: You MUST have a working market. Follow this thread or this thread for more excellent info (and work) on enabling the Market.
Simply replace the Vending.apk in /system/app/ with this file (rename it Vending.apk first), reboot, and you are good to go! I would recommend backing up the original Vending.apk so that you can replace it if anything should go wrong for you.
You can use Root Explorer with /system/app in r/w mode, but it is simple to do via adb as well:
adb shell mount -o remount,rw /dev/block/mmcblk0p5 /system
adb shell mv /system/app/Vending.apk /system/app/oldVending.apk
adb push Vending.apk /system/app
**If you have problems, simply delete the Vending.apk, and replace it with the oldVending.apk
There is a newer version of the Market posted by devis and Xhorder in this post. Please use it instead. It fixes the weird star artifacts of this version. Instructions are exactly the same.
DO NOT simply click it to install. If it happened to work for you that way, you were lucky. You really should replace the Vending.apk with this file. Also, I saw one user report that the search function didn't allow Market searches. I believe they are the only one with that issue, and I'm not sure how they installed this. I assume they did not follow instructions, as my guide backs up the original file, and the person with the issue is asking for the orig apk. So, YMMV, but follow this instructions, and you should be fine.