Have you first checked the music plays ok in iTunes? iPhone supports same formats as iTunes. It does not support WMA. iPhone userguide: http://manuals.info.apple.com/en_US/...User_Guide.pdf page 12 onward for synching. Page 73 for manual updating your iPhone. This might be worth a try.

This was copy-pasted from iTunes help menu:

To sync media with your iPhone:

Connect your iPhone to your computer (make sure the iPhone has been activated).

When the iPhone appears in the iTunes window, select it.

Click the tabs (Music, Photos, and so on) and select the items you want to sync.

To sync only certain items, click Summary, select “Sync only checked songs and video” checkbox, and then click the other tabs and select the items you want to sync.

Click Apply.

You can sync your iPhone and your computer any time by choosing File > Sync iPhone.

If you don’t want your iPhone and your computer to sync when you connect your iPhone to your computer, deselect “Automatically sync when this iPhone is connected” in the Summary pane.

If you have problems syncing, try syncing only certain information. For example, deselect the Sync checkboxes on the Info, Photos, Podcasts, and Video panes, and try syncing only Music.

Another article, about if you use Genius: http://support.apple.com/kb/HT2978