Hi Andy,
It depends on a few factors, firstly distance i.e. bluetooth and wireless both have different distances from which they can operate, and also what other features your PDA has included in it.
Ontop of that you can then work out which method is best, sending data in 1 go every nth seconds or streaming it live to a computer, plenty examples of TCP/IP and bluetooth exist under LabVIEW examples (Help > Find Examples > Search)
Once you can narrow down the communications protocol you wish to use I can help you further,
Thanks,
Applications Engineer