Regression testing is nothing but once the bug is fixed we 
need to test wheather that fix can make anyother problem 
elsewhere.

Integration testing is nothing but checking the interface 
between the modules.

Vinod...what you tell is absolutely correct....but in 
practicle scenario ..when u used integration testing and 
how....what i know as a functional tester...this is not 
very much our cup of tea...it is much more ...development 
side testing>>>>>But when a new module is integrated in you 
present application, then what you do as a blackbox 
tester...Integration or regression.....?

Regression TEsting:- retest on a modified build is called
regression testing.
Integration TEsting:- testing the interaction between the
module is called Integration testing

Regression Testing:
To check the new functionalities have been incorporated 
correctly with out failing the existing functionalites.
Integration Testing:
Testing of combined parts of an application to determine if 
they function together correctly. The 'parts' can be code 
modules, individual applications, client and server 
applications on a network,

Regresion Testing:
re testing the modified build to check that it has any 
effect on the other functionalities and this is done by the 
Testing Team

Intergration Testing:
this is the testing which is done by development team to 
combine all the modules to one entire application.