The fact that agents can search your computer when you cross international borders presents special problems for attorneys, given that our computers likely contain information we are ethically bound to keep confidential. If you are considering international travel with your laptop, I recommend that you check out Bruce Schneier’s column on crossing boarders with your laptop.

Bruce’s advice for your best defense:

So your best defence is to clean up your laptop. A customs agent can’t read what you don’t have. You don’t need five years’ worth of email and client data. You don’t need your old love letters and those photos (you know the ones I’m talking about). Delete everything you don’t absolutely need. And use a secure file erasure program to do it. While you’re at it, delete your browser’s cookies, cache and browsing history. It’s nobody’s business what websites you’ve visited. And turn your computer off – don’t just put it to sleep – before you go through customs; that deletes other things. Think of all this as the last thing to do before you stow your electronic devices for landing. Some companies now give their employees forensically clean laptops for travel, and have them download any sensitive data over a virtual private network once they’ve entered the country. They send any work back the same way, and delete everything again before crossing the border to go home. This is a good idea if you can do it.

I urge you to check out his entire post. Also remember that they can search your phone/PDA in the same way that they can search your laptop.