Technology conferences are fine places to pick up vendor swag and free gifts — after all, if you’re going to travel across the country or across the ocean, a little token of appreciation is certainly in order — but the web productivity and collaboration Office 2.0 Conference, starting this Wednesday, has taken the notion to a delightful extreme.

Every paying attendee to San Francisco-based O2con (press and bloggers are not included, darn it) will receive an iPhone 4GB model along with the $1500+ conference ticket; the iPhone will be used to manage conference contacts, schedule meetings with other participants, view schedules, chat & tag photos, and generally serve as a guide to the event. This grand experiment will result in a gaggle of more than 500 simultaneous iPhone users in the same place, on the same WiFi network. The conference app will be running on the Etelos web engine/CRM platform, seen here (bonus points to Etelos for captioning the screenshots in Comic Life, very nice touch).

As you might expect, some attendees would prefer an 8GB iPhone; they can upgrade for a mere $115. Those already packing an iPhone can change their free gift to a Playstation 3 running Linux (really, just as nice). Conference attendees who have received their iPhones are posting their impressions, raves and gripes (including a bout of domestic strife when two teenage girls became outraged that their mother had an iPhone before they did) on the O2con discussion boards.

If you’re attending O2con, let us know how it goes and whether you’re enjoying your “free” iPhone.