Today I installed the latest Snow Leopard update so I could access the new Mac Apps Store (located under the Apple menu). I "bought" the free Twitter for Mac program and the installation went flawlessly.
I am going to stick with YoruFukurou as my primary Twitter client, but I do like the new Tweetie 2.0 (which is what Twitter is) because it lets me create several unsent tweets at once, work on them and then fire them off all in a row. Otherwise it is an overly stripped-down program, without even the option of larger fonts.
When you install 10.6.6, be absolutely sure to run Disk Utility and repair permissions both before and afterwards. It found hundreds of items to update. Also click Verify Disk when finished. Mine came out fine. As always, download the Combo Update instead of relying on the smaller and simpler updater from 10.6.5 that Software Update provides. You will find it here.
If you'd rather I do it I have it with me so let me know.
The App Store is actually a separate application from the iTunes Store, although you log in with your iTunes username and password. It's been reported widely that the security of the store has been cracked already and there will be pirate versions of Mac apps available elsewhere on the Net, some of which may contain malware. The applications on the store itself should remain clean, though.
I am also happy to report that the conflict between Flip4Mac (Windows Media player) and iTunes 10.1 has been fixed with updates to both. Current iTunes is 10.1.1 and Flip4Mac is 188.8.131.52.