Of course
 

Unless the program is licensed under an open-source license such as GNU(which iTunes or any other ipod program is not) It is very illegal and if for any reason you are caught, you can get either fined a lot of money or thrown in jail(if you think it is still worth it go ahead)

Why not contact the Samba group /Andy Tridgell and ask them. They're obviously in a very similar position but have not been prosecuted & their stuff is used by many people/companies. I would guess they know a lot about the legalities that apply...

the samba group? Did they reverse engineer everything they've done? Huh, see that's the kind of thing I'd be interested in. They haven't been prosecuted at all? huh....thanks chrism...

You're very wrong. Decompiling is perfectly legal. Copying the original source is not, unless the copyright license allows for that.

And as far as EULA is concerned: cases trying to prosecute reverse engineering on bought off-the-shelf products are generally tossed out. EULA or not you do have rights that you cannot waive through the click of a button.

Somehow people are in fear of any EULA but look at it this way: the EULA for GAIN specifically forbids uninstallation/removal of their software through any means other than the add/remove software control panel, that you cannot reverse engineer their software to figure out how to remove it, that you cannot advise others to uninstall that piece of shit, cannot remove it through automated or manual means, and cannot develop utilities to remove the software. They neglect to include the uninstall applet in add/remove programs. How long do you think any such EULA would hold up in court?

If reverse engineering were illegal, most of gnu/linux would have been shut down years ago, and Microsoft would certainly have shut down WINE long before it became mature enough to run Office, MSIE, and other Microsoft applications.

A lot of work on linux is a result of reverse engineering. Drivers of all sorts are just one example. Basically if there is something, anything, a lawn mower as a fan.If you can make it work for you without stealing, then you can do it. By the way, DVD John broke the itunes code, wrote sharpmusique, lives in San Diego, and Steve Jobs hasn't knock on his door with a law suit.