I know Mango has been out there for a while and writing about one of its new features could be boring but I recently discovered the "Internet Sharing" options in the WP7 settings.
Normally when I travel and want to use g3, I boot my laptop, plug in the g3 dongle, start the provider software, wait till the dongle is recognized, type in the pin, wait till g3 connection is available,connect, wait till I'm connected (1 to 5 minutes).
Then the train station gets nearer and I have to switch the train, so plug out the dongle, hibernate.
Switch the train and start all over again.
Now when I use WP7 Internet Sharing, I start my laptop, enable Internet Sharing on my WP7, connect to my phone per wireless LAN, and start surfing.
On the train station I just hibernate and in the new train I reconnect to my phone.
It’s so much more comfortable that i felt forced to write about it :)
So if you want to try it out, just go to "Settings"->"Internet Sharing" and start browsing.
If you aren't traveling alone you can share the internet with up to five clients.