Looking for new wallpapers for your Voyager? Going to places like Zedge,no or other reputable Wallpaper sites with a library of iPhone papers will do,
Just download the iPhone wallpaper of choice to your computer. While you're at it, download a program at Download.com called ifranview.
Load up the wallpaper into Ifranview and click "Image"
In the "image" menu, you'll find a option to Resize / Resample the image. From there you can resize the image to the 240x400 for the external screen and 400x240 for the internal.
pretty much 95% of the iPhone wallpapers will look great on the Voyager. From there just plug your phone into the computer using a dat cable, go into tools, scroll down to USB Mass Storage Mode and if you have a memory card (Which You Should) put the respective files into the my_pix folder.
and TA-DA.... new wallpaper.