yep.. i use a hp ipaq 1710.. got pocketstars, pocket universe and thesky on it.
Preference for me is probably pocket stars.. as it has a fair bit of functionality and is alot less resource hungry as thesky.. pocket universe seems to be the lightest of the three. If you've got system memory to spare and a fairly fast processor in the o2 go the thesky though.. in my opinion its the best of the 3 in terms of functions.
the all have a 'night vision' mode.. but they're all poor in the night vision preservation.. i got an old pda wallet thingy and hot glued some red celophane too it.. then when i want to use the pda for observing i just slip the pda in
But I took home a new lappy today(2nd hand) specifically for observing cause it was cheap

I've loaded starry night pro on(i love it!) and I'm gonna try get a perspex red screen made up for it. I'm actually using it right now

I used my work lappy a couple of times when i was out observing but I doubt work would be happy about the lappy being covered in dew

plus the last time i used the work lappy i spilt a little bit of coffee in it :/
let me know....

el