About a month ago I found a 70s radio station on Live365.com called The 70’s Preservation Society. This is THE best internet 70s station I have listened to.
One of the things I like about this station is how they divide up the content between days. For example Tuesday is Classic Rock day (they even have a live request show in the afternoons), Wednesday is Disco, Thursday is Top 40 and etc.
Give them a listen. You can go to http://www.70ps.com/ and click the now playing symbol on the right side of the banner.