If you're on the go, doing three shows a day at a marine park, it's hard to keep up with e-mail, and text messaging can be a real time-suck. Thankfully, with the prices of smartphones coming down, these all-in-one cell phone PDAs aren't just for business travelers anymore. Over the last week, I put three of the hottest models to the test to see how well they combine form, function, and aquatic versatility.

First up is the offering from Palm, the grand-daddy of smartphone manufacturers. The Palm Treo 680 ($199, Cingular/AT&T only; H) is lighter than its predecessor, but some say it's still a little clunky. Personally, I don't need a phone to be tiny. If it's too small, it's more difficult to hold in your elongated jaws. Plus, I find that the small keys on Treo's QWERTY keyboard make precise typing difficult.

So far, not so good. But how does it work underwater?

Terrible. The Treo 680 fizzled and died as soon as I dove down three feet. I didn't even get a chance to test its web-browsing capabilities before it shorted out completely.

It's easy to get complacent when you've been one of the big kids on the block, and Palm has done just that. They have to learn to adapt to the needs of their diverse customer base, not the other way around.

We all know the BlackBerry Curve 8300 ($TBA, Cingular/AT&T only; HHH) is going to be good at e-mail—that is, after all, how the BlackBerry became a complete necessity for 21st-century business—but how does it work as a phone? My handler Bob helped me call a friend of mine at the Shedd Aquarium in Chicago. The reception was good, although to be fair, that's more a function of the network than the device. And due to the small speaker in the earpiece, some of her high-end clicks and squeaks were lost, making communication less than ideal.

But what happens when we take it to the bottom?

Disaster. It only worked for 40 seconds before it quit altogether. Another disappointment from the narrow-minded engineers at Research In Motion, who have left themselves very vulnerable by focusing so singularly on their current target market.

Like everyone, I got seriously geeked the moment I saw Steve Jobs introduce the Apple iPhone ($599, Cingular/AT&T only; HH) at Macworld. It seemed to be what every gadget-obsessed dolphin is looking for in a next-generation handheld: sleek, stylish, and multi- functional. And what's more, it had a delightful wallpaper with a placid marine setting.

In the four months since its unveiling, I've been swimming back and forth, just waiting for my chance to try it out. Then, out of the blue, I was contacted last week and asked if I wanted to give it a test run. Does a tuna taste delicious? When the Apple rep arrived, I was so excited that I did a double backflip and splashed Bob.

The touch screen handled surprisingly well. I could easily toss the phone into the air and bounce it off my nose to dial, so calling can be fun. Let's be honest, though: It may be called the iPhone, but no one I know is interested in it just as a phone. It's the widescreen video iPod functionality that has the tech nerds excited.

Frankly, I was disappointed by the pedestrian offerings by iTunes. I was looking for episodes of Flipper, or The New Adventures Of Flipper, or the movie version of Flipper, but I settled for the Mel Gibson action film Ransom. I had to wonder if it was really worth my time and $10 to watch it on such a small screen, where a lot of the nuance of Gibson's performance was lost. I suppose it's better when you hook it up to your large-screen TV, but that's another connector and another $20.

When I was satisfied that it seemed to work well on dry land, I took it straight to the bottom of the pool. After five seconds, the screen went black and the device became unresponsive. I was so furious I leapt out of the water and hurled the iPhone at the poor Apple rep, who made a rather sheepish exit.

Once again, the aquatic mammal sector has been completely ignored by the major cell phone manufacturers. Given their track record, I shouldn't be surprised.

Drop by next week when I kick the tires of the new 2007 toasters.