Brighthand has a great article chronicling all the patent infringement lawsuits currently plaguing the handheld industry. It's truly a mess. On one hand, patents are designed to give the little guy leverage against large companies. On the other hand, I think if you're going to patent something, that something should exist. You should build it, and your patent only sticks if you actually have the physical implementation. Lawsuits like the current one E-Pass has filed against pretty much every PDA maker might make sense if (a) you'd ever heard of E-Pass and (b) they actually had a product.
I did a quick bit of poking around on the E-Pass web site and found that the phrase "patented interactive smart device" appears in the metatags for every page, and each page contains keywords including "palm pilot", "patent" and "wallet PC". I checked out www.e-pass.com on Alexa and found that while the site has been running for seven years, only seven other sites link to it (all of them news articles about the patent lawsuit), and their site's traffic rating is 1.9 million.
In contrast, I run a small site called MohairSofa that offers a single, free PocktPC application. Very small site, very simple product, no revenue. MohairSofa is ranked 1.3 million by Alexa and has twenty-six sites linked to it. Perhaps I should sue someone. After all, it's not hard to come up with an idea, and apparently, I don't even have to prove the idea works. Just make it broad enough, and sit on it until someone else creates it and markets it. Hell, I hear the beer in the fridge calling now...