Please answer dis question...It's helpful 2 so many!!!

TEST STRATEGY:
Before starting a testing activities the team lead will 
have to think a lot and arrive at a strategy.This will 
describe the approch,which is to be adopted for carring out 
test activities including the test planing activities.This 
is a formal document and the very first document regarding 
the testing area and is prepared at a very early stage in 
SDLC.This document should give the overall scope of project 
at a high leavel.
 
TEST PLANS:
these are prepared by experienced people only.In all test 
plans the ENTRY -TASK -VALIDATION -EXIT criteria are t0 be 
mentioned.ENTRY means the entry point to that phase. TASK 
means activities that is performed.VALIDATION is the way in 
which the progress and correctness and compliance are 
verified that phase.EXIT tells the completion criteria of 
that phase ofter the validation is done.

I think the answer posted by Venkateswara Reddy is somewhat
incorrect. Test Srategy is prepared by the PM i think, not
the TL.

I think sri is correct test strategy is prepared by PM

Test Strategy:  This document is a organizational level 
document and is prepared by the PM.  This document contains 
the details about the whole testing approach, methodologies 
etc.  

Test Plan:  This document is prepated by the Test Lead.  It 
consists of the testing details i.e. 
who is going to test
what would be environment
what is in scope of testing
delivery dates
risks and contingencies etc.

Who prepares what is very least bothered here, it depends 
on the experience of the resource and organization 
structure.

Coming to the questions asked....

The basic fundamental is

Test Plan - What to test? (resource, schedule, environment 
etc)
Test Strategy - How to test? (methodologies, design 
techniques etc)

Test Strategy is part of Test Plan (Master Test Plan)
Test Plan contains Scope, People (Trining, expereince),
Incidents (which reports, when), Criteria (Entry Exit,
Resumption), Risks and Assumptions, Environment,What not to
test, and Test Strategy for main modules/functionalities or
links to that documents.


Now to the question who prepares, In my orgnisation, Test
Stategy is prepared by TLeads, and even Sr QE who has good
exp in that functionality. 

In other compnay it might be different.

Test Strategy is a formal document that is to be prepared 
at the early stage i.e once SRD and MPP is baselined.

Test Strategy tells about the overall plans for that 
release.To be more clear it tells about the scope of 
testing,resources involved,Entry and Exit 
Criteria,Risks,Assumptions,Environment used.