Hi
My father was a GI who met and married my mom during WWII and I have traced my family in the US. He was born in New York, later moved with his family to New Jersey where he enlisted in the Army.
You will be able to apply for his military records and can start this process online. Although you do have to print out the application and send it airmail as they need a signature
http://www.archives.gov/veterans/evetrecs/but I just want to warn you that there was a fire in the early 1970's and lots of records were lost (my dad's were) but hopefully you will be lucky.
Do you have his Army discharge papers? I might be able to help you with deciphering the abbreviations.
The 1930 census is online as is available with a subscription, I do have one so if you need help just PM me and I would be happy to look him up.
His SS application is also available (I think it cost about $25 when I applied) it will give you excellent information.
Let me know if I can help in any way as although it appears complicated to research on the other side of the Atlantic, it is relatively straight forward when you know how

Yvonne
I have just checked Rootsweb SSDI which is free to search, just enter his details and you will see on the right hand side, a link "SS-5 Letter", which is a letter that you can print and send. The cost is $27