Web sites

http://ramya-moorthy.blogspot.com/

http://www.perftestplus.com/

LR Bible:

http://www.wilsonmar.com/1loadrun.htm

http://www.performancewiki.com/

http://www.javapassion.com/javaperformance/#Performance_tuning_methodologies

http://performancetesting-loadrunner.blogspot.com/

http://shashank-khandelwal.blogspot.com/

http://www.loadtest.com.au/Terminology/ResponseTime.htm

Capacity planning

http://msdn.microsoft.com/en-us/library/ff650695.aspx

http://www.jds.net.au/tech-tips/top-loadrunner-blogs/

http://loadtester.tumblr.com/archive

load Balancer:

http://www.loadbalancing.org/

http://jmeter-tips.blogspot.com/2010_10_01_archive.html

http://ptsperformancetesting.blogspot.com/

http://commonlrissues.blogspot.com/