The stories are circumstantial at this point (i.e., Steve hasn't come out on stage and said “We own Pod,” but they are certainly growing.
Anybody remember PeaPod.com? Actually, just checked, they're still around (who would have guessed?). They were first – they should sue Apple.
Or what about the foreign film from 83, The Pod People? Can they sue?
Cruchgear writes on this subject (in reference to one of the cease and desist letters that “However, in Mach5Products’ case, the owners claim that they thought of the name back in 2001, before they heard of the name iPod. But will that make a difference? Probably not.“
My general take here: Apple, you own this market. Play this right and everytime somone orders from Peapod or watches bad scifi, they'll think of you. Start acting like Microsoft and their Zune project just might have a chance.