need help with parsing form input ...

Greetings. I'm out of my league here, not knowing enough about regular expressions yet to do this, so I desperately need someone's help ... I need to parse form input to eliminate unwanted characters (punctuation, mostly) ... for instance, if the web site visitor types " smith,susan--33" into the field, i want to parse that line to eliminate the initial space, the comma, and the dashes so that $myvariable=smithsusan33" .... any help in doing this would be GREATLY appreciate. thanks.