validation help (checking for those nasty chars)

I have seen many examples using ereg to validate email addresses, but none for checking the so called "nasty characters" such as #!{}. etc. While I consider myself a step up from a php rookie - whatever that may be - I don't have a strong perl background and thus ereg calls look very scary to me ;) So far I have gotten along fine with strstr. If anyone could steer me in the right direction that would be appreciated. - Craig Simons