well, an indirect way would be to go to the link in the navigation frame, the one refering to the page you want to print, and right-click on it, then choose "open in new window"... you can then print the page from there.
The method Po describes does work in some cases. However, a number of frame sites will force the creation of the frameset when you try to display the page outside of the frame. I'm not sure if you can print individual frames in Mozilla. If not, we'll track that "bug" and see if that can get added when fixed. If this is specific to K-Meleon, I'll make sure it is on the list of improvement requests for future releases.
i'm not sure how mozilla handles frames, but in IE 5+ (it may be part of one of the 'enhancement packs'... i don't remember; i just get used to it being there...) there's a menu item - "open frame in new window" - when you right-click anywhere in a frame that isn't an image or a link... mozilla willing, this might be a nice feature for k-meleon. it's useful for screen viewing as well as printing.
I know that's a fairly common feature in most browsers. I just checked Mozilla 0.9.5 and it allows you to open just a single frame in the existing window or open a single frame in a new window. Both are handy features. But, some frames detect when they have been opened outside their frameset, using javascript, and will force the frameset to be built. So, the best way to handle printing still is to have an option in printing to print a single frame.
I worked as a web developer, and I do not use the above mentioned feature request that often, but I do use "view frame source" context menu option very often. And since I switched to K-Meleon for my daily surfing, I missed that very much.
Please consider this as an endorsement to "individual frame processing" feature request (I meant that it includes opening, printing, saving and view-source).