The future of podcasting has been thrown into doubt after Apple Computer threatened to sue a small Texas company called Podcast Ready, claiming the company’s use of the word ‘podcast’ violates Apple’s trademarks for the iPod personal music player.

Apple’s move, part of a broader crackdown on the use of the word ‘pod’ by potential rivals, prompted widespread criticism from bloggers and others involved in the medium.

“No one confuses a podcast with an iPod, any more than ‘car wax‘is confused with a ‘car’,” wrote Dave Winer, an early podcasting advocate, on his blog, Scripting News.

Last week, in a letter to Podcast Ready, Apple’s lawyers said customers were “likely to be confused and mistakenly believe” that the company’s Podcast Ready and MyPodder product were associated with Apple.

Podcast Ready makes software that delivers podcasts to portable music players and other devices, including the iPod.

“While Apple . . . has no general objection to proper use of the descriptive term ‘podcast’ as part of a trademark for goods and services offered in the podcasting field, it can not allow marks that go beyond this legitimate use and infringe on Apple’s rights in pod and iPod,” the letter said.

Apple’s move to control the term podcasting marks an escalation of the company’s campaign against products whose names its says risk infringing the iPod trade mark. Apple had previously sent cease and desist letters to companies making products such as the TightPod, a line of fuzzy computer carrying cases, and Profit Pod, a device for monitoring arcade games.