Hi Sarah,
There are many apps for that. Here's a quick synopsis along with my thoughts on each (I have used every one, though it's been a while and some may have improved):
Remote RDP ($5.98)
* Windows-only.
* Requires "Remote Desktop" to be configured on the PC.
* No custom software on the PC required.
* Only works if your Phone can directly contact your PC.
* Quality is pretty good; usability is a little clunky.
Remote VNC Pro ($1.98)
* Works on any VNC-capable PC (Windows, Linux, etc.)
* Requires a VNC server installed and running on the PC.
* Only works if your Phone can directly contact your PC.
* Quality is lower than Remote RDP; usability is a little clunky as well.
I believe there is also a free VNC client out there. It is a little buggier than the Pro one, but has about the same characteristics.
PhoneMyPC ($4.99)
* Windows only (at this time).
* Requires PhoneMyPC client software on the PC.
* Works from anyplace, any time (as long as your Phone has Internet access).
* Quality is decent; some bugs remain (it is in Beta). Usability is high (easy pan and zoom, mouse control)
To look at these, go here:
remote | Paid | By date, Androlib, Android Applications and Games
Search for
pc remote
To learn more about PhoneMyPC, click it's name in my signature.
Hope that helps!
Scott