DigiGuide is a powerful UK EPG program for Windows. It's far more flexible and usable than the Sky EPG, and can provide TV listings for up to 10 weeks in advance (minimum of 2).
There are skins and plugins available and the program can also display listings for channels from other countries in various formats (for example XMLTV) using a converter. Users can also create and share their own listings to add into the program.
And all of this a year for the price of a couple of months worth of TV Times.
Personally, I've been using it for years and wouldn't be without it - the future program search and reminder system, for instance, is superb.
Click here to visit their site for a 30 day free trial.