How often hasn't it occured that you are at a customer location and you want to test the Exchange connectivity.
The Microsoft Exchange Team has launched a test site now so you can test the connectivity without the hasle of having a remote pc to test it.
https://www.testexchangeconnectivity.com/
Currently the following Tests are available.
- Autodiscover test for Outlook 2007
- Outlook 2003 RPC/HTTP test
- Exchange Activesync test
- SMTP Inbound Test
I think these guys are doing great work.
And ofcourse like you're also told on the website, use a test account and not your domain admin account to do the tests.