While the English speaking Estrada in the USA, most from the several Mexican lineages, may be blessed with the greatest ammount of information on their US ancestors from several religious and governmental sources, experience shows that they find the greatest obstacles when they reach the first foreign ancestor, and seldom can they go further up. Unfortunately, getting records in Mexico or other countries is not too easy and one has to beware of scam artists who will readily take your money and supply you with false information, if at all.

A search process that is very useful is through the several search engines.

Go to the search engine: Yahoo!, Google, etc. and write your last name in the search window. You will get a myriad of replies, from which you can refine your search.
For general genealogical information, type Genealogy in the search box and select the genealogical service that may best suit your need. Some services are free, some are not. You must be aware that most will set cookies in your computer and some will set several, which means that they will be getting information from you and it may be used as they see fit, including selling your name to bulk mail services. Some cookies are necessary, so I have set my browser to ask wether I accept a cookie or not. I always read the notice carefully before accepting one.

Some links that may be useful and/or interesting are:

Dick Eastman. His Web site has interesting and valuable information, especially about genealogy scams. http://www.eogn.com

Estrada Family Genealogy Forum:
http://genforum.genealogy.com/estrada

The Estrada Surname Group at Yahoo!:
http://groups.yahoo.com/group/Estrada-surname/

A useful link: http://en.wikipedia.org/wiki/Estrada