There are three major types of wireless communication that are compatible with current PDAs.
Bluetooth (BT): This is good for very short-range communication b/n two or more devices. Most common use is with the wireless keyboards and mice for desktop PCs and the wireless earpieces that are so popular for cell phones. PDAs use BT most often for communication to accessories or for short distance wireless communication to a particular PC.
WiFi: This is more widely used to allow wireless communication to the internet via an access point. This is what is used in hotels and coffee shops when they advertise, “Wireless internet capable”. It has a longer range (up to a few hundred feet depending on the hardware) and can allow for multiple users at one time.
The third uses cellular technology. Since this one requires a Phone/PDA hybrid device, I won’t go into that one too much. Just understand that with the new crop of Phone/PDA devices, you can get on the internet anywhere you have cellular signal. It costs more, but is pretty darn convenient.
What you are wanting is the WiFi type of wireless. You can buy a card like this one to plug into your Jornada. This will allow you to connect in places that have a publicly accessibly access point. I’m not endorsing this particular brand; just showing you what one looks like. You can buy a newer PDA that has this and other wireless capability internally installed. I have an Ipaq 2755 that has WiFi and BT. This means you don’t have to pull a card out each time you want to connect. Also there have been some real advances in the screen technology and memory size in these devices. You may want to check out some newer ones to see if you want some of these newer features.
I would suggest, however, that if you are happy with your Jornada, aren’t interested in newer features, and only need wireless infrequently, you buy a WiFi card and use that.
If it ain’t broke, don’t fix/replace it…and all that.
Best of luck.