If you share an interest in historical time cycles, you might like to make contact with Edward Cheung's Longwave Press and the Longwave & Social Cycles Resource Centre. You can also join the Longwave List from his site.
You might also take a look at Bill Murray's Time Page, where he summarises the main ideas of Strauss & Howe's book "Generations".
Eric von Baranov has a good description of Kondratieff and his wave, together with a list of reference materials.
The Canadian Banff Centre has put together a brief description and chart of the Kondratieff Wave.
The Journal of World Systems Research is also worth a look.
Most of these sites include links to other sites of interest in the study of cycles.
You can go to the Contents Page for a list of Cycle Pages;