I just got a voyager too.
I just figured it out
1. install the USB driver that came with the phone on the CD, just the driver not the "vcast" program.
2. plug in your phone, under settings and tools go to the USB msass storage option(you must have a microSD card installed in the phone)
3. The phone should show up as a removeable drive on your computer. copy any MP3s or WMA's you want to the phones "my_music" folder
4. at this point they should show up on your phone
You might say that MicroSD's are to expensive but I bought mine on sale for $5 for a 2gig, I actually saw them pop up about 2 months ago on woot, but I bought them knowing they were a killer deal and I would find a use for them. Now I bought my phone 2 days ago and I have a use for one ... I used the other in the digital camera I bought last week.