Originally Posted by tatonka_Hero

Espresso is basically just a theme, gives a square bar at the bottom instead of the standard round one.

As for your voicemail problem, go to Menu>Settings>Call>Voicemail settings, and enter your phone number (you might have to select "my carrier" under Voicemail service first).

WiFi tether I have no experience with, no use for it.

I'm sure there's a theme/taskbar out there that'll bring you back to a stock taskbar...I haven't messed with it yet (I agree about the signal icon though)