2 sets of contacts on my iPhone

Interesting, but that's not how it works.

If you are using MM to sync your contacts, do not also sync them to your computer. If you do, you will get two sets of contacts, one from the cloud and one from your computer. If you are using MM, de-select "Sync Address Book Contacts" in itunes when you sync. If you do that you should get a single set of contacts, that is how it is designed to work.

Karth - that's what I said...
"Yes I think this is a glitch and should be fixed in the next patch".

We should NOT have to disable one list of contact to get rid of the duplicates. It should work out of the box like it did before OS3 release. So when we disable one list, it's just a quick work around of the problem. Some people think that it's duplicate by design but I disagree.

So just to clarify - if you have two sets of contacts - one from 'On My Phone' and another that are done through the cloud by MM - you should disable the push contacts in MM and stick with the manual syncing of contacts through iTunes when you plug your iPhone into your computer?
Is this the only way to do it? It's frustrating me!!!

some people chose to disable push on MM and sync on computer. I did the opposite, by deleting a copy on the iPhone that was sync'ed via computer and use MM's push to sync. There are several ways to do this as well.

One way to do this is... [http://www.macosxhints.com/article.php?story=20090617052238509]
which says...

On the iPhone, I deleted my MobileMe account, and then set it up again. When I then turned on MobileMe syncing for calendars and contacts, the iPhone told me there were existing records, and did I want to merge them with these newly-synced records. I said yes for both contacts and calendars, and that was the end of the duplicates!

In stead of deleting MM and adding it back, I just toggled MM contact & cal off and on again.. seems to have the same effect since they both ask what you want to do with the copy on iphone and once you add MM or turn it back on it'll ask if you want to merge the list... say yes.

Thanks that worked perfectly. Appreciate the tip.

YES. Tootser is correct, Craig is not.