A cheaper alternative to the Socket cordless adapter is the Aircable one. I got mine plus cables from
http://www.astrocables.com/
Have a look at Astromist a very full featured sky chart for the Palm and now the Pocket PC's. The also offer a discount on the Aircable adapter if purchased via Aircable directly.
Another software for the PPC that caught my eye was Tachyon looks very good also.
I bought my Aircable blutooth serial adapter from Astrocables because the sold the cable to power it from the Autostar.
I have the HX4700 but I have yet to use it for star charts. I prefer the laptop for that. The pocket PC would be ok if I was just setting up for Visual use. But as i am imaging an need the laptop it just makes more sense to use that.
Regards
Fahim