When I bought my Mac, I had to ask this question. I had to ask myself the very same question. Windows Mobile will only sync with a Windows PC running Windows Vista or Activesync with earlier versions of Windows.
Luckily for those of us who have made the switch to Mac, there is a product called The Missing Sync for Windows Mobile. I am now able to sync my Sprint Mogul (ppc-6800) over bluetooth to my Macbook. All of my contacts, appointments, and even my photos I take on my phone are synchronized with no trouble.
Missing Sync for Windows Mobile can sync much more than I have it doing. One thing that it will do is sync your music library with iTunes. They have Missing Sync for Palm OS, Missing Sync for PSP, Missing Sync for iPhone, Missing Sync for Nokia, and Missing Sync for Blackberry available.
The Missing Sync for Windows Mobile is available for download at http://www.markspace.com/ . Missing Sync for Windows Mobile costs $39.95, but it is money well spent if you need to sync your phone with your computer.