Did you know that the coolest tool in your kit might be your public library card?

In most states, you can get a library card from a public library outside of your county of residence -- as long as you can prove state residence (true for the San Francisco Public Library). Often you will have to go the actual state library in person to pick up your card, but once in hand, you can access the library from the web. Fanatical researchers are known to have a wallet full of library cards from numerous public library systems within their respective states. Some states, Ohio and Michigan being two of the better known, have statewide consortiums of private, corporate and public libraries, which allows you access to the combined services and databases licensing power of them all.

If your local library system does not provide free online access to digital content databases, the cheapest way to get into these expensive databases is to pay for a library card from the New York Public Library. The NYPL offers membership to non-residents of New York, a privilege which also enables you to remotely access its online databases. For a $100 annual membership fee, non-residents will get a card that provides remote access to about 85 of its 300 online databases, although this card sadly does not include the JSTOR database of scientific journals. (New York residents can get the same card for free and obtain the same level of access.)

Another advantage of your digital library card to the NYPL (and others): They offer a rapidly increasing list of good e-books, audio books, and videos available for legal downloading. There's nothing like getting a squeaky-clean free copy of a best-selling "book-on-tape" to port to your iPod.

The New York Public Library is not the only major library to offer memberships to non-residents. If you live anywhere in California, I recommend getting a library card to the San Francisco Public Library, which is free, and which does give you access to the coveted JSTOR online journals. Only downside: you need to show up at the library in person to get your card.

I want one. Going to SF will be hard for me. It's a long and expensive trip into the heart of darkness but I'll do it.