Despite some uncertain rumors (Page 2) that Apple may be working on WMA for iPod, there are further hints that Apple has avoided this route. According to an article in the Wall Street Journal (Paid):
Musicmatch President Peter Csathy says Musicmatch users can transfer songs purchased on the site to more than 60 portable devices that support Windows Media. Musicmatch says it has asked Apple to let its users put their songs on the iPod, to no avail
Also, in November 2003, when Steve Jobs was asked about Apple supporting WMA, Steve Jobs said "We decided to support an open audio codec standard [AAC] rather than a proprietary one. [WMA]" .... "That's our plan and we're sticking to it. We're feeling real good about it too".
Of course, the HP deal may have introduced new considerations, but there is no strong evidence to that effect.
Update: From what appears to be a very reliable source, Apple is not currently planning on introducing WMA support in either the HP iPod or regular iPod.