I have a v551 also (great phone btw!) and I use a data cable. I used to have a v60 (AT&T TDMA) back in the day and thankfully Motorola has kept the same connector on the bottom of their phones since then. Decent cables can be purchased off eBay for relatively cheap (about $5 before shipping last I checked).
To use the data cable, you will also need some software as Windows does not recognize it as a removable device (Windows sees it as a GSM modem). You can purchase the mobilePhone Tools from Motorola or your wireless provider, which will include the data cable (Motorola has it on their website for $60: link). Assuming your provider is Cingular, I know you can also purchase this accessory in store for a similar price but you will probably want to call to be sure.
If you took the eBay route, download it off the internet; I can't post links for legal reasons but let's just say that Google can be very helpful. You can also use third-party software, such as P2KMan, but these are less user-friendly and less intuitive.
If you run into problems, I would submit your questions over at Howard Forums; they are very knowledgeable and helpful in all things wireless (both phones and providers).