WordNet (r) 3.0 (2006):

rumormonger
    n 1: a person given to gossiping and divulging personal
         information about others [syn: gossip, gossiper,
         gossipmonger, rumormonger, rumourmonger,
         newsmonger]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "rumormonger":
   a tale-bearing animal, busybody, gossip, gossip columnist,
   gossiper, gossipmonger, newsmonger, newspaperman, quidnunc,
   reporter, scandalmonger, tabby, talebearer, taleteller, tattler,
   tattletale, telltale, tittle-tattler, yenta