Add to the list of programs that let you remotely observe another computer's screen. The latest Mac OS X-compatible release of the Internet telephony and video chat program brings remote viewing of a buddy's screen, along with an interesting per-minute fee for Wi-Fi access at commercial hotspots. Both features are available in release versions only for the Mac; the current Windows 4.1 beta .
Screen Sharing -- Skype 2.8's screen sharing lets you share your screen with a buddy, who can only observe, not interfere (consider the Prime Directive!). This may be enough for demonstrating a point or answering a question, but insufficient for technical support or collaboration.
Instead of requiring that you share an entire screen, Skype's approach lets you share just part of a screen via a floating window that you can resize during an active session. You initiate screen sharing by selecting a buddy, and then choosing Share Full Screen or Share Selection from the Call > Share Screen menu. You can also initiate screen sharing if you're already in a session with someone from the gear pull-down menu.
In our testing, Skype's screen-sharing feature worked - even during the beta period - when iChat was incapable of starting a screen-sharing session no matter which party initiated and who had control. ( screen sharing always adds control to the party viewing a screen, just like .  has observe and control modes, with separately configurable permissions.)
Hotspot Access -- Skype 2.8 also brings Wi-Fi hotspot access for your Mac at for-fee locations around the world, paid by the minute from credit in your Skype account. , as the feature is called, works with what Skype says are 100,000 hotspots worldwide, enabled by Boingo Wireless.
When you're at a hotspot supported by the software, a message appears offering you access. I've seen this pop up in Starbucks, which is operated by AT&T as part of about 20,000 U.S. locations the telecom firm serves.
Rates are: in U.S. currency, it's 19 cents per minute, or in the euro zone, 14 euro cents per minute (value-added tax may be added depending on country). That's $11.40 per hour (plus tax), which contrasts unfavorably to day rates of  throughout its U.S. network and as much as $30 per day in the most expensive European hotels. Hotels and airports more typically charge $8 to $15 per night.  its direct subscribers $10 per month for unlimited access in North America, and $59 per month for 2,000 minutes per month of usage worldwide. Neither plan requires a commitment beyond one month.
For casual use, such as 5 to 10 minutes of hopping on at a given location, Skype's pricing relative to most day rates is far more worthwhile.
Skype also claims that voice and video quality have been improved in the latest release, but I haven't seen a difference in my use.