The two main rules:
1. Do it for the right reasons.
In comments to a recent blog on Working for Free, Sheryl and Kelly describe some of the right reasons to do pro bono work. Giving back (to your community, to a cause that's dear to your heart, to your church, etc.) is at the heart of most pro bono design work. Other reasons for doing volunteer work are important as well but will differ from one person to the next. You can gain valuable experience, build your portfolio, and perhaps expand your horizons beyond the type of work you normally do. ?You might get work somewhere down the road that is directly attributable to your pro bono work, but don't do it just for that reason. Down the road could be a dead end.
2. Use a contract.
Working pro bono only means you're not getting monetary compensation for your work. It doesn't mean you aren't providing a valuable service or product for your client. Protect yourself and the client by using a contract. Spell out exactly what you are offering pro bono and what you aren't. Typically, you supply the design work but the client pays for the printing. Or, arrangements are made to secure pro bono or discounted printing services. Either way, spell it out in the contract so you aren't left with a bill you weren't anticipating. If you are expecting some sort of tangible non-monetary compensation (such as credit line/link on their Web site or a free ad in the company's newsletter) put it in your contract. Just as with paying clients, if you require a certain number of printed samples for portfolio use, include that requirement in the contract. Even though they aren't paying for your design services, non-profits, charities, churches, and family can all potentially be picky, even demanding, clients. ?Or not. Be prepared either way to deal with demands on your time that you might not have intended when you volunteered.
6 Tips for Doing Pro Bono Web Design - Good advice here although I don't necessarily agree with #6. Sure, sending a statement showing what the client would have paid is fine, but I'd make it clear that it's not an invoice right up front, no "make them sweat" games.Drawing Up a Contract for Pro Bono Design Work - Mulitple designers who do a lot of pro bono work chime in here with advice on using a contract, what to put into a contract, and dealing with nice and not-so-nice clients.Business of Design Online: Working Pro-bono - Scroll down for a list of good article and advice on why to work pro bono and how to find pro bono jobs, drawing up contracts, and even a sample pro bono contract. Pro Bono Work Questions - The main thrust of this Graphic Design Forum discussion is giving up rights to your work and what you can reasonably ask in return (a credit line every time a logo you designed is used, probably not reasonable).Improve Your Portfolio With Pro Bono Design - David Airey tells us that "Pro bono publico (usually shortened to pro bono) is a phrase derived from Latin meaning 'for the public good.'" It can be good for your portfolio too. He explains how to approach a business about doing pro bono work.