If I want to legally use material copyright by a company, I want to "license" that material, right? Is there a common starting point in contacting someone about this? Is there a standard fee or percentage or something that could be expected? Is it likely to be worthwhile to a shareware developer?

There is no standard I''m afraid. It depends on how valuable what you want is and how good a negotiator you are. Could include an up front payment then a per unit royalty or just a royalty. If the thing in questions is of low value AND the owner believes you are passionate enough about their creation they may even give permission for free.

It is unlikely to be worth licensing for an indie. To benefit from licensing something you need people to know and that requires marketing spend (which further increases the cost). Unless you can make a pretty good business case (show significantly increased sales) to cover this cost it is unrealistic to license something just because you think it is cool.

One of the strengths of an indie is low cost. Play to your strength rather than trying to compete in the same league as mainstream devs/publishers that are license driven. Your license wont be as big and wont generate more sales so stay away.

Dan Marchant
Obscure Productions (www.obscure.co.uk)
Game Development & Design consultant