everywhere I go I get a network connection called hpsetup, but I don't
know how to access the internet with it. What is it and how do I use
it?

hpsetup is the default network name for 'ad hoc' wireless network
connections for equipment suited for a wireless network when there is
no access point.

Sinds you don't know what is sending the signal the following steps
might help to set up the connection and tell you to what you did
connect:

Setup the PC
Use the software that came with the 802.11b card to configure an Ad
Hoc profile with the following settings:

    * Communication Mode: Ad Hoc
    * Network Name: hpsetup
    * Network Security: None

Information about the hpsetup network used by HP Printers can be found at:

http://h10025.www1.hp.com/ewfrf/wc/genericDocument?cc=us&docname=c00040410&lc=en

But I guess you don't carry your printer around all the time...