Using wireless is not that difficult, I have an X3i and a
wireless network setup in my home.  Yes, you can surf
open networks that are in public places.  The keyword
here is open though, if you are using a pay service then
you will be required to log in securely to their network
using the credentials that they provide you.  I have
found though that in a lot of places there are open
networks that you can use, just be sure that the network
owners encourage you to use it and they are not just
missing something by not locking down their network.  In
the X3i there is a tool built in (as soon as you press
the button on the far right) once you enable the wifi.  
Click on the gauge that appears in the lower right hand
corner of the screen.  It'll bring up a tool where you
can do a site survey and it'll show you if there are any
nearby networks.  Look for the ones where the little lock
looks unlocked.  These are the ones that you should be
able to access without any credentials.  The ones that
are locked are using the WEP (wireless encryption
protocol) and you'd need a username/password or possibly
an unlock encryption key to use them.  good luck and hope
this helps.  Oh yeah, one more thing, Distances on these
networks is pretty small, maybe 300-500 feet on a good
day so you'll have to sit still while using them.