One of the challenges with using the Windows version of popular notification system Growl is that it doesn't always play nicely with all applications. Skowler aims to fix one such challenge: using Growl to provide notifications from Skype.
Skowler lets you set up notifications for when you receive or miss a call or when selected contacts come online. You can also set up hotkeys for frequently dialled contacts. It's a pretty early-stage project in beta right now so check the installation notes on the site before trying it.
We've mentioned Growl for Windows in the past, and while it hasn't gained the fanatical following of its Mac inspiration, it is a potential option for more customised notifications of activities on your PC. I'm not a big Growl user myself, so I can't pretend to comment on how effectively Skowler works; if you decide to give it a go, let us know how it goes in the comments.
Skowler is a free download for Windows users.