The % key is one of the best features of vim: it lets you jump from { to }, [ to ], and so on.
Howeve
I'd like to expand on Greg's answer, and introduce the surround.vim plugin.
Suppose that rather than editing the contents of your quotes, you want to modify the " characters themselves. Lets say you want to change from double-quotes to single-quotes.
foo(bar, "baz quux")
^
The surround plugin allows you to change this to
foo(bar, 'baz quux')
^
just by executing the following: cs"' (which reads: "change the surrounding double-quotes to single-quotes").
You could also delete the quote marks simply by running: ds" (which reads: "delete the surrounding double-quotes).
There is a good introduction to the surround plugin here.