We are still trying to assemble all the bits and pieces but it looks like Sprint was preparing the 2.1 upgrade for tomorrow, May 14th but uploaded the updater and the new instructions today.

A user of SDX-Developers by the name of chrisfeltdrum was downloading what he thought was an older, previously released in February update, when he realized the OS version he upgraded to was actually Android 2.1.

Chris immediately posted this information to the SDX-Developers forum for confirmation, and in a matter of minutes other users have confirmed the update was indeed official 2.1 and not the old Feburary release.

I went to the sprint download site to reload what I thought was CL14 back on my Moment. After install, I noticed something was different with my phone. My phone read Firmware 2.1-update1, S:M900.8.OS.DE03, Kernel version 2.6.29, ECLAIR.DE03, HW version M900.8.0

Did sprint release 2.1?? If so, where's the live wallpapers?

it's actually a different size if you download it...
old one was 87 mb  (Checksum:  cc8f95d7d2b80a349cdf7cecb1390abb)
this one 101 mb...  (Checksum:  d1acafb81e643533afd15bbc8cd7b443)

Samsung Moment Android Eclair 2.1 Update Goes Live Early, Available Now From Sprint, Already Rooted

Download

To get your update, which will unfortunately require a full wipe, head over to Sprint's Moment software page and find the Download link at the bottom.

The refreshed update instructions, mentioning May 14th, can also be found on the same page - here is a currently working direct link.

Sprint is unlikely to pull the update, now that it's out, but in case they do, you can head over to the SDX-Developers post where you will find some mirrors.

Root

According to the forum members, an existing root method v7, created in anticipation of the final release, is still working. That's is an awesome job and our hats are off to the devs at SDX-Forum:

Samsung Moment Android 2.1 Update Goes Live Early, Available Now From Sprint, Already Rooted

We are confident that It is not going to take the crew at SDX-Developers to incorporate this new update into their custom ROMs and release them to the public.

Did you download the update? If so, how did it go and is it everything you've been waiting for?

Sources: