There are about 20 different post at various sites about how and where to get the 2.1 upgrade. Every site and post had so many different links, updates, fixes, etc that it was frustrating if you're new to this. Youtube has a video instructing on how to upgrade, just type in "2.1 upgrade". It's broken into 3 parts as you will see.
I found this to be easier, although I had tons of help from dreze88 aka the rockstar. The Youtube dude goes very slow (too slow if you ask me), so you can take your time and get it right. He tells you to email him for the links, and it takes no more than 2mins to get the links back from him.
In case you don't want to email him, I'm leaving them below. Good Luck.
Links that he will send you:
Samsung Updater software from Sprint link: Sprint Software Downloads - Smartphones - Samsung Moment with Google
- Just click on "More Details" then at the bottom click on Download. Then save to Desktop or wherever you want.
Android 2.1 for Moment link:http://www.game-connect.com/sprint/SPH-M900_MR2_DD03_REL.7z
- Don't forget to install the Jzip he mentions