@sunny: Hard to say. Some fruit teas are incredibly fruity naturally. I had one at a tea place that was like... fruit juice. I think they put in fruit flavoring though, not necessarily jam.
@sunny: I'm not particularly well-versed in tea, but boy do I like a good strong flavored black tea.
@Lina: Honey in tea is good too!
@0v7: Honestly, I think I'd be more inclined to put jam into green tea and sugar into black tea. Not that I do that, but the black teas I drink are very rich flavors that I'm not sure would really work with lighter fruity flavors. That's just me though!