T-Mobile and Windows Vista have got together to give new Microsoft Vista customers free complimentary T-Mobile Hotspot usage until April 2007. Laptop owners with Linux, Microsoft XP or MacOS will still have to pay (unless they do what I have written below).
T-Mobile’s wireless Internet at Starbucks or Borders generally costs $9.99 for one day unlimited use or $29.99 and above for monthly usage.
If you do not have Windows Vista, yet want to use T-Mobile’s Wi-Fi freely, follow the steps:
1. Change your user-agent string to show this:
Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
To change your user-agent string in Firefox, you can try this Firefox extension called User Agent Switcher.
Add a new entry and make it look like this:

I do not know how to spoof the user-agent in other browsers like IE, Opera, Safari, etc, but there should be a way.
2. Test if your browser is spoofing Vista by clicking here.
You should see this:

If you see your regular operating system (and not Windows Vista), it means you have not entered the user-agent string correctly. In that case, repeat step 1.
3. Go to T-Mobile’s Vista signup page here. Create an account for yourself and browse the Internet freely at any T-Mobile Hotspot like Starbucks or Borders!