Chris Pirillo posts "Should Wi-Fi be Free?", commenting on the rumor that Starbucks will soon offer free of charge wireless Internet at their locations.
Currently, T-Mobile provides Wi-Fi at most Starbucks locations; exceptions include 'captive' stores, like airports, which are typically belong to the food service provider that owns the relationship with the port. I'm happy with the arrangement: I have a T-Mobile account, so I get connectivity for $20 per month. It's secure, allows VPN access and available at a variety of places besides Starbucks that I frequent. Yes: I actually go places besides Starbucks, if you can believe it.
Chris points out there is a ton of free Wi-Fi out there. Access is available via a gamut: "Wi-Fi Roguing" (stealing wireless Internet from unprotected networks) to public, freely-available Wi-Fi. Use your search of choice (I use the Windows Live Hotspot Locator) to find the Wi-Fi nearest to you.
I cannot comment on the veracity of the Starbucks rumor, but strongly agree with Chris on his concerns that non-commercial / non-sponsored Wi-Fi may not be secure.
Granted, free Starbucks Wi-Fi, whomever the provider, falls into the 'sponsored' category, as does your local coffee shop, community center, etc. I would expect sponsored Wi-Fi to be legitimate; safe from folks who might collect credentials. Since you really don't know the operator, this is a risk, and I suggest the use of a Smart Card or secure proxy.
When roguing, you're totally at risk when you connect to an unknown network; whether owned by random private individual whose condo is in range, or some punk with a laptop putting up a familiar (think: 'linksys', 'netgear' or "Free Public Wi-Fi") SSID.
Hell, even commercial SSIDs run the risk of being spoofed. See "Wi-Fi Access Point or Account Credential Honeypot?" for a detailed walk-through of my observations with AT&T's public Wi-Fi.
If in doubt, don't connect.