The Motley Fool has an excellent three-part general information article about IPOs.
You can find information on Initial Public Offerings (IPOs) at CBS MarketWatch
Hoover’s Online IPO Central provides a wide range of information about IPOs. The IPO Central has sections on IPO Filings, IPO Calendar, IPO Performance, IPO Scorecard, IPO Update, and IPO List.
EDGAR Online, Inc. has an IPO portal which also provides information on IPOs.
Another place to find information on IPOs is the New York Stock Exchange Web site, which has an online IPO Showcase sorted by year. You can also find information on IPOs at the NYSE Web site by entering “IPOs” in the search box at the top right of the NYSE Web site.
Lastly, CNN Money also has an IPO Center.