This is a very welcome feature that saved my day at various occasions, you can turn your iPhone into a wireless hotspot and share its mobile data connection.
I will show you how to enable desktop notifications, so you will notice a new email, even if you are not in the window where you have your Gmail account open.
The new Nokia Here Maps have an option that enables you to download maps to your iPhone or iPad via Wi-Fi, so there won't be any data connection needed the next time you will be using the app.
VMware player is a great free tool for creating virtual machines and desktops. For instance, you can create a new virtual computer to install and test the new Windows 8 Consumer Preview.
If you are a heavy twitter use, possibly with more then one account, than I suggest you to give Tweetdeck a try. You can arrange, schedule, monitor and manage your tweets with ease.