Does exist (Advance, Comprehensive, Powerfull) - Serious URL where we can find equalent components. Without Purchasing. My search capabilities returned this (for me dissatisfied but not bad) sites, here are:

Analog Cross Reference Search
http://www-s.ti.com/sc/docs/psheets/crossref.htm

NTE Electronics Semiconductor Cross Reference Search
http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm

Transistor Cross Reference Database
http://www.ee.washington.edu/circuit...rts/cross.html