Double-press the Fn key and it will enter into Fn Lock mode so you can type all the `blue` characters without pressing anything. Press again to return into normal mode. Same goes for Shift - double-press to enter Caps Lock mode...
Click on the status area and you'll find there a Bluetooth on/off button.
No, it doesn't, unless you are using POP3. Use IMAP or MfE servers if available.
They are quite decent for bundled earphones, if they keep falling off - put wider `foam` heads on them - you get 3 different sizes with your N900...