Well for software, look at Skyscape.com and Epocrates.com both have some free software that is great. On some of my books, I ordered with accompaning PDA software (my med dict. and drug guide) and I plan on purchasing a med abbreviation software, a NCLEX review, RN Notes, and maybe a care plan software. I haven't started school yet so I don't know how truly useful the free software is, but I am sure it will be very handy--it includes dosage calculations, drug interactions, conversions, etc. I can't wait to have all that at my fingertips when I start clinicals!!!
Be sure you get a memory card if your PDA doesn't have a lot of memory--these programs are pretty large! My PDA, an "old" HP, had only 25MB of storage. I now have a 1GB SD card, with plenty of room to spare. My PDA is an older model not equiped with Wi-Fi or recording capabilities or a bunch of other stuff to be had on newer models but it will do everything I need it for!
Good luck on your search!