I can't think of an alternative music sync option off hand, though you've got Orb and various options for streaming music.
As for agenda (assume that means tasks), contacts, calendar, there are quite a few options.
Google Sync will let you wirelessly sync contacts and calendar, just as one example. Pocket Informant will do calendar and tasks (and is due to add notes and contacts in future updates).
Toodledo, Remember The Milk, various others offer online sync for tasks plus native apps to sync with those. Things and Omnifocus both offer superb Mac desktop plus iPhone tasks mgmt apps with wireless sync ...