Using keyboard with other languages

Good morning. Brand new to MacBook Pro. I am trying to find out how to use the US keyboard and type accents in various languages.
In PC there is a setup to US International for keyboard during windows installation. Is there anything similar here and how to do it?
Thank you very much for your kind attention
Regards
Rakham

I want to make sure my question is clear. For instance I want to have 10 años instead of 10 a~nos or élèves instead of 'el`eves!
I want to use the keyboard as it is and not to modify the values of the keys.
Thanks and regards
Rakham

Try these:

http://www.apple.com/macosx/tips/keyboard11.html

http://www.apple.com/macosx/features/international/

An Apple rep showed my sister that iWork can display a floating keyboard in multiple languages. (gotta love those macbook pros!)