In theory, you can issue a "307" Response, which is supposed to tell the client to "Redirect" to a new URL, using the same method (ie: if the old was a GET, do a GET, if the old was a POST, do a POST with the same data)

The problems with this are:

• Old Browsers may not have any clue what to do with a 307.
• The spec explicitly says that a client shouldnt' follow a "307 Redirect' without confirmin this is OK with the user (since they may not want to send their data to the new URL)

for more info on the existence of 307, see the note in section 10.3.3 of that RFC.