It doesn't matter if you have a mac or PC, ipod touch or not. Subscribe to this podcast from iTunes. It is called Photoshop User TV. The whole thing is run by NAPP (National Association of Photoshop Professionals). It doesn't matter if you have Photoshop or not (or Lightroom for that matter). This podcast is all about tips in Photoshop and Lightroom. If you like that podcast then check out two others, Ask Dave and Lightroom Killer Tips. Ask Dave is run by Dave Cross, who is also in Photoshop User TV. Lightrrom Killer Tips is run by Matt Kloskowski, who is also a part of Photoshop user TV.
P.S. Don't have Lightroom? Get Lightroom 3 beta 2 for FREE here!!! (Yes, it is fully legal)