A researcher has found what appears to be a serious exploit in Skype. ComputerWorld has the details but given how fast Skype reacts to things like this, my guess is this will be cleared up quickly. Still the news is reminiscent of the kind of issues Internet Explorer ran into.
ZDNet has more details and show exactly the result of the exploit.
Skype provides a full description on its Security Blog of the vulnerability and the steps that have been taken to address the problem so it doesn’t affect users – http://share.skype.com/sites/security/2008/01/skype_cross_zone_scripting_vul.html