I want to buy a Quad-Core Xeon E5420 processor, but a web-store told me that it has been discontinued. So what is the replacement part, or where do I go to find out what the replacement part is? Thanks.
See http://qdms.intel.com/dm/d.aspx/D3388293-BDFA-41DF-801C-8F6BD5D94558/PCN109873-00.pdf - you should still have a chance to place order before Oct. 2010.
You may try to find a local dealer on http://premierlocator.intel.com.
The later generation (Xeon 5500/5600 series) uses a different socket and won't fit your current system.