You mistyped the abbreviations. It is DV and PFD. Check out the Common Abbreviations link llecs posted. DV is debt validation. A timely DV letter will require a debt collector to cease collection activity until they provide the required response (which really isn't that much). Run a search for DV or debt validation and you'll get all the details.
PFD is pay for delete. It's basically a contractual agreement that the creditor/collection agency (CA) will delete negative information in exchange for payment of the debt. There are issues in negotiating a PFD. For example, if the debt is still inside the statute of limitations, you want to be careful sending a PFD unless you are able to pay the full amount as you could be sued on the debt. Again, if you run a search for PFD, you should find lots of threads. You can also run searches in the rebuilding forum for PFD and [name of CA] to see which CAs are more likely to agree to PFD. If you can't find anything, post about the specific CA and people will share their experiences, if any.
Starting Score: ~500 (12/01/2008)