Excel formula to take out quotations

Use SUBSTITUTE to find and replace text - =SUBSTITUTE(some_text,"""","") will replace all double quotes with nothing. (There are four double quotes in the second parameter because you have to double them inside strings - otherwise Excel interprets it as the end of the string). So you could use:

=SUBSTITUTE(WEBSERVICE("http://finance.yahoo.com/d/?s="&A3&"&f=p2"),"""","")