From the Canon au website:
http://www.canon.com.au/en-au/For-Yo...R-Cameras/450D
Live View
Yes
External Interface
Hi-Speed USB, mini B port / Video OUT (NTSC/PAL) / Wireless
Remote Control Terminal
Yes (RS-60E3 compatible)
Given the above, it appears that you should be able to connect the 450D to a PC with the supplied USB cable and using EOS Utility with Remote Live View, control the camera from the PC.
Cheers
Dennis