TEST PLAN :- A test plan is a systematic approach to 
testing a system such as a machine or software. The plan 
typically contains a detailed understanding of what the 
eventual workflow will be.


Test plan contains the below fields:-
a) Test plan identifier;
b) Introduction;
c) Test items;
d) Features to be tested;
e) Features not to be tested;
f) Approach;
g) Item pass/fail criteria;
h) Suspension criteria and resumption requirements;
i) Test deliverables;
j) Testing tasks;
k) Environmental needs;
l) Responsibilities;
m) Staffing and training needs;
n) Schedule;
o) Risks and contingencies;
p) Approvals.

Basically Test plan will be prepare by Testing Lead. Tester 
will just gotrough the document and write the testcases and 
executes.

If any thing wrong let me know 
rajeshreddyvasa@indiatimes.com