In white box testing the tester should/will know the inner
workings of the code.And this will be done by the
tester.This can also be called as glass box,structured,clear
box,open box testing.

Unit testing is the basic testing done by the developer to
see whether the code is working fine.Each module will be
tested by the developer before sending it to the testing team.

White Box testing is  a Testing technique used to Perform 
Unit Testing.In Unit Testing we will test each individual 
program by using White Box testing techniques like Loop 
Testing,Statement Coverage,Condition Coverage...etc

If anything mistake please write cmments...

Regards,
Shailu

White box testing is something in which the tester must 
have a basic knowledge of a language which is being 
used.Unlike Blackbox,this is someting which is also called 
as Glass box, where you have an access to the source code.

Unit Testing: A type of WBT,generally done by 
developer.Basically its done at module level to catch and 
fix the most obvoius bugs, so that they should not make to 
the Integration level.As compare to Integration testing 
fixing issue, found during this level of testing becomes 
very easy,as developer knows that in which module issue 
exists.

generally whitebox testing and unit testing are same. in 
other side in balckbox testing, functional testing is also 
called as unit testing.

defination of unit testing generally:testing the 
functionality/output of a perticular unit or block.

In white box testing: developer will check for the each and 
every line of code for the exact output.so checking each 
and every line like a unit, so called unit testing.

In black box testing: testing team will check for 
functionality of an each field or each option/parameter.
each parameter/field is like a block/unit. so we can call 
it as unit testing.

finally, there is no industrial standard defination for 
these.but the principles are same in both whitebox and 
black box testing.

please correct me if i am wroung.......

regards,

lokesh karanam