An HTC Phone can be used as an excellent modem. One can always connect to the internet through PCs or laptops using the HTC Phone . To enable the modem functionality HTC Sync 3.0 has to be downloaded and the Data Connection feature of the HTC Phone has to be enabled. To complete the synchronization process, the phone has to be connected to the computer and by selecting the Internet sharing option, the process will get complete. With revolution in telephony, the HTC Phone will always keep its owner connected to the internet. This process is, however, applicable only for Android 2.1 based phones from HTC. A compatible operating system on your computer with an internet phone package and a USB cable are all required to complete the process.
Here's how to use your HTC phone as a modem, connecting your PC, netbook or laptop to the internet and allowing you to browse webpages, send/receive emails and use your instant messaging software, anywhere and at any time:
Source Official HTC website