Where is this Twitter App hiding? I changed my twitter password a while ago, and periodically, when my phone has been off or totally offline, I'll get an alert: "Twitter sign in failed" but the Icon looks like a twitter icon, not Seesmic or Tweetdeck, the two apps I use. I'm assuming the problem from the app perspective is that my password isn't working. From my perspective, the problem is that I can't even figure out what app is sending these prompts. Seesmic and Tweetdeck have my new password, and I don't see a "Twitter" app in my applications anywhere. 

How do I even begin to figure out where this alert is coming from?
It's probably the Social Networking Service (SNS) or a similar application, rather than a Twitter-specific app.  I have this service on my Samsung phone and there's a widget that can display social networking posts on the home screen.  You can manage it via Settings -&gt; Accounts and sync, as Al said.