Warning Only works with Skype versions prior to version 5.3 (because 5.3+ removed Skype Extras Manager for Plugins like this one - thanks Skype)
Future Spec. Call Manager for Skype
If you have a Skype online number and want some extra control over who can call when or want to know who is calling then give Future Spec. Call Manager a try.

Check Straight To VoiceMail to send callers straight to voicemail (if you have Skype Voicemail) during the hours entered and if you want people on your contacts to be able to call anytime then check Except For Existing Contacts.
If you want to know who is calling (Google the Caller ID) then check Google Unknown Callers. This will open your default browser and google the incoming phone number, if it's not from one of your contacts.
If you would like to buy the pro version and be able to set rules for each contanct, email
sales@ftrspec.com with your requests.
Minimizing the program will place it in the system tray. Click icon in tray to bring back up options window.
The first time you run the program you will need to authorize it in Skype.
Requirements:
Skype Versions 3, 4 or 5
.Net Runtime 2.0
Windows XP, 7 (32/64 bit versions)
Download and run exe, no installation necessary.