The ARRL maintains the latest band plan chart in PDF format: Download here.
I find myself referring to my chart all the time, as I’m still learning the edge limits of the bands.
This latest chart has been updated as of March 5, 2012, to reflect the new changes to 60 meters.
Another nice site regarding DX: DX Code Of Conduct
I saw this link on on the QRZ.com page of a Venezuelan station I was just trying to work. Ironically, it wasn’t good DX, as the operator never copied my call 100%. His signal faded into QRM not long after.
A nice article on Working DX HF Pileups. I think I have been operating properly in most cases.
At any rate, these tips confirm what I suspected: That you simply need to be patient and persistent when trying to work DX, although sometimes you just aren’t going to get through. Find another station to work and move on!