DailyTech has officially published AMD’s plans to discontinue certain processors. This is to rationalize its production and launch a price war against the Core 2 Duo :

This document confirms the end of the Athlon 64 X2 AM2 equipped with 2x1 Mo of cache L2, as they will no longer be able to be ordered by AMD clients after June 28th and deliveries will last until December 31st. AMD will also stop the Athlon 64 4000+ and 3700+ with 1 Mo of cache in a rather brutal with shipping only lasting until July 2nd. The A64 X2 4400+, A64 3200+ and 3000+ Socket 939 will be shipped out until the end of the year.
For the Sempron AMD is also cleaning house and is stopping the 3300+, 3100+ and 2600+, that have 128 Ko of cache on the Socket 754. Orders will be taken until June 28th and shipping will last until the end of the year.