When you feel it's time to work on a site upgrade, I hope you'll consider an HTML5-friendly video-player, and/or an iPad/iPhone Guitar Tricks app. I have to agree with the other posters: Apple isn't going to come around -- those who want their content to be viewable on Apple mobile devices are going to have to update their sites.
In the end, I'm not sure Apple agreeing to offer Flash on their devices would even solve the problem. As a person with a Flash-friendly Android phone, I have to say, the mobile Flash experience is very poor. Flash is extremely frustrating to watch on my Flash-enabled phone. For example, if you watch Lisa's video on your homepage on my Motorola Droid, the video is extremely choppy -- even with wi-fi. It would be almost impossible to learn by watching her fingers in a tutorial video. The sound doesn't even match the video.
One site that has done a nice job upgrading their video is Lynda.com. Those videos run beautifully on the iPad and on my Droid. Other sites, not wishing to upgrade all of their content, created an app just for viewing video. They may not include ALL of their content (take the ABC app, for example) but they include enough to keep users entertained.
Anyway, I'll be sticking around -- iPad compatibility or not -- I love what you guys do here, and I've learned a ton! I'm looking forward to even more lessons -- keep up the great work!!