"The circuit will put a signal that is surprisingly sinusiod onto the line provided the appropriate transformer and primary capacitor are selected. "

Please note that the "appropriate" in the above is a big one! If you can handle that, then the suggestion as given by MJK is a nice one.

If you have difficulty with such discrete parts and still want a good sine wave, the only ( and with less headache) option would be an XR2206 or ICL8038 as suggested by Kai would be the way to go. And it will free up processor resources for more useful things.

Raghu