As part of our national 6m initiative, we have put together a list of useful links on 6m.
A good introductory discussion on 6m propagation modes by K1HTV (note that this is a US article, so the summer/winter months should be reversed for VK):
Great 6m website:
Six Metre International Radio Club (SMIRK) 6m links:
DK5YA 6m links page: