In order to participate in an IPO, one must be a customer of one of the underwriting banks (special exceptions may exist), these banks would let you know of the exact dates as they become firm. One cannot determine exact dates just from an S-1 filing, as the companies still have to go through their whole roadshow/ investor wooing period. If you want to see the SEC's list of companies that intend to go public, it's on their site:

http://www.sec.gov/cgi-bin/browse-edgar?company=&CIK=&type=s...