A short while ago, CCP deployed their new Stackless IO technology to address the lag issues in Jita with great success. Now, Stackless IO has been deployed to the entire EVE cluster and to be honest, things seem faster.
You can read the entire dev blog on the CCP website:
http://myeve.eve-online.com/devblog.asp?a=blog&bid=588
Good discussion, as always, can be found in the comments to the dev blog:
http://myeve.eve-online.com/ingameboard.asp?a=topic&threadID=886913&page=1
