WASHINGTON - Leading Internet companies, in an unusual joint effort among corporate rivals, announced six lawsuits Wednesday against hundreds of people accused of sending millions of unwanted e-mails in violation of the new federal law against "spam." The legal actions by Microsoft Corp., America Online Inc., Earthlink Inc. and Yahoo! Inc (NasdaqNM:YHOO - news)., represent the first major industry actions under the "can spam" legislation that went into effect Jan. 1. The suits were filed in federal courts in California, Georgia, Virginia and Washington state. Dozens of those named were identified only as "John Doe" defendants accused of e-mailing unwanted...