Am I a UK citizen?

I am confused about whether I am a UK citizen or not and I am looking for clarification.

Here are my facts:
•   My dad was born in England in 1902 (I have his original birth certificate)
•   My Mom was American
•   My Dad went to USA as a young man and met my Mom
•   They married in 1930 (I have their original marriage certificate)
•   My dad became a US citizen before I was born (I have the certificate, as far as I know he never renounced his British citizenship)
•   I was born in 1946 (I have my birth certificate stating my mother’s and father’s names
•   I married and divorced (have both certificates)
•   I married and divorced again (have both certificates again)
•   I married a UK citizen in 1989 (have certificate) and am still married to him
•   We moved over to England in 2003 and I received my ILR at that time.

I believe I am already a UK citizen based on my ancestry.  Is this true?
If that is the case, can I simply apply for a UK passport by providing the documentation I have?   (I’d rather just pay the fee for a passport than go all through citizenship application and fees if I do not need to do that.)

When I applied for ILR I did not realise that I was already a British citizen (if it is true that I am).  When I received my ILR I did not need to take a Life in the UK test. 
I want to apply for my British passport.
1.  Will I need to take a Life in the UK test?
2.  Will I need to send in my US passport with the application?
3.  Can I used a document checking service for this?
4.  Can I go to Newport myself?
5.  Once I apply with proper documentation do you have an estimated idea how long the passport will take?

I appreciate and advice on my questions. 

You can apply for British citizenship by descent, yes. Would have been a lot easier than going down the ILR route!  I don't think you have to take the test, but don't quote  me on that. I'm sure someone else will know the answers to the rest of your questions.

**I don't think you have to apply for citizenship, I think you are already a citizen and just apply for a passport!  You'll need your dad's birth certificate, of course, and if he still has a British passport (expired or not), you might be asked to provide that...

From what I understand, as long as your father was married to your mother, he was able to pass on his citizenship to their foreign-born children automatically.

This is the page regarding passport applications:

http://www.direct.gov.uk/en/TravelAndTransport/Passports/WhoiseligibleforaBritishpassport/DG_174145

Hope that helps!

**It's only us foreign-born children of British women who have to go through the hassle of applying...

See also Chapter 2: Automatic acquisition - persons born before 1 January 1983

Welcome back to 'vinny the link'! 

phillygirl, I agree with others the fact that you will get the Brit passport because your dad was a brit

Just make sure that when you apply for the passport that you have his & your long detailed version birth certificate & include their marriage certificate

it would help also if you have one of your dads old UK passports

The more you send them the faster it comes back

My daughter got hers in seven days because we gave them more than they asked for - learned from when my son applied

side note, under the British nationality act your mother having married your dad prior to 1949 would have been an automatic british citizen

Thnk upi all very much for your replies.  I will let you know how it goes.