I assume this is your phone: http://www.gsmarena.com/htc_chacha-3787.php
If it isn't then you can disregard this post.
I'm not sure this will work with your specific phone but I've used Android phones to connect to the Internet before, and as long as your phone isn't horribly crippled it should work as well. First connect the phone to the computer and select "Menu -> Settings -> Wireless and networks -> Tethering and Portable Hotspot" and enable USB tethering from there.
Then on the computer you need to run
as root to load the usb network driver (if it isn't already loaded). You'll see the new interface by running ifconfig, and from there it's just like starting an ethernet connection from the command line.
# ifconfig <ifname>
# dhcpcd <ifname>
I hope this helps, but as I've never used your particular phone before I don't know if it requires any special steps or even a completely different procedure.