unit testing means testing the application by module 
wise.it is also called as component testing.it includes 
statement coverage,branch coverage,loop coverage.
  
Functionality testing means testing the application wrt 
funtional req.

unit testing is performed by developer (or) white-box 
testers.

functionality testing is performed by black-box testers

Unit testing:
                 Unit testing means It tested single peace 
of code or module....
             This test is conducted or white box test 
enginner.whitebox test engineer should have internal skills

Functionality Testing:
             Functionality testing Means it tested all the 
functionality is working or not according to the customer 
requirment ......this is called Functionalty testing

In Unit Testing Tester is supposed to check each and every 
micro function.In most case the Developer will do this
Functionality testing is to test against system 
requirements and confirm that all the requirements are 
covered.

Unit testing means testing the piece of code..

functonality testing means testning system functionality.
testing the overall and perticularbehaviors and functions.

At Coding Stage, programmers are verifying the internal 
structure of every program with the  hwlp of white box 
testing techniques

Balck box type testing geared to functional requirements of 
an application; this type of testing should be done by 
testers. This doesn't mean that the programmers shouldn't 
check that their code works before releasing it(which of 
course applies to any stage of testing)

Unit testing means testing the application by module 
wise. In this testing covers statement coverage, branch
coverage, component and loop etc. 
Unit testing covered by only developer.

Functionality testing means testing the application with
respect to function wise.