No service on phone - use wifi?

i was under the assumption that w/o a sim card & no current service provider i'd be able to use public wifi signals. what is the exact line of demarcation between a "smartphone" and a regular phone? my phone has android 2.2 OS, & 1ghz processor, is it "smart"?

via Forums de téléphone cellulaire (en français) http://cellphoneforums.net/fr/general-cell-phone-forum/t363813-no-service-on-phone-use-wifi.html