"All you need to do...", as these things always start, is to decide on whether you want them powered only when the bike is switched on or all the time. Then get a spare DC power lead for each - you are going to start by cutting this up to expose the internal wires. I would probably recommend not chopping the one you are currently using, just in case you decide you want to go back to the plug in method (or things go tits up in the process). Find out which of the leads in the power cable you are chopping up is live and which is earth - it isn't always clear. This may mean a bit of digging in the documentation for your device. If they make a specific "automotive" lead then use one of those. If there is an in-line fuse supplied on one wire then that's the live feed.
Identify a handy earth wire or point in the wiring loom near where you want the connectors to meet the equipment. Connect both earth cables from the power leads to that wire or point. Identify a live feed wire in the wiring loom (either ignition switched or always on as decided above) and connect the live feeds to that. A nicely coloured wiring diagram and a multimeter helps here. Neither the PDA nor the bluetooth receiver are likely to take much current but you should plan on sticking a fuse in-line somewhere between that connection and the device to protect them against surges and spikes.
Now connections can be either Scotchbloc quick connectors or the bigtrailbikerider approved soldered and heatshrink sleeved spliced connections. There are various discussions on this site as to which should be used - the latter is superior and will have fewer worries about getting wet but it can be fiddly and dangerous for other wires if you try to make a soldered connection to what is a fairly tightly packed wiring loom without some experience of doing such work.
You might be beginning to get the feel that this is quite difficult - well, it is if you don't know what you are doing. I wired in a spare set of lights on my bike and learned the practical bits that way. I took time, read lots of things on this site about what to do, and had some previous experience of working with a multimeter and soldering iron (and in the end I used Scotchblocs as my skill wasn't up to a good soldered joint). If you can get the cables, or are willing to risk your existing cables, I'd really recommend having a word with Steptoe to see if he could do it, or your dealer about getting them fitted by a man in overalls as part of another job. It doesn't take long - tank off and battery disconnected, wire in connections, battery reconnect, tank on and finish - so it won't be as expensive as, say, melting the insulation of a couple of wires by accident or connecting to the wrong cable, having to reconnect elsewhere and patch up the originals.
Oh yeah, and think about how you are going to protect those connectors when they aren't in use. You don't want to get them (a) regularly wet or (b) touching live and earth to something which will conduct electricity. The mount for my GPS has a little rubber "hat" on a string to cover the power connector when not in use. You'll need to find something like that if the cables don't come supplied.
Hmmm. Sounds a bit discouraging doesn't it...