UPDATED: On Thursday, Google stopped issuing ID numbers to investors who want in on its IPO, in preparation for the opening of bidding, which began Friday morning.

Google and its underwriters will announce the final price for the shares next week. It set a mind-boggling range of $108 to $135 in its SEC regulatory filing, but bidders don't have to stay within that range. The stock will trade on the NASDAQ with the ticker symbol GOOG.

But the IPO may hit a huge bump in the road. On Friday, Google revised its S-1 filing to warn investors that a profile of founders Sergey Brin and Larry Page in the September issue of Playboy, which hit newsstands today, "presented certain statements about our company in isolation and did not disclose many of the related risks and uncertainties described in this prospectus."

SEC rules prohibit companies preparing to go public from activities that could be seen as hyping the stock, as well as from selectively disclosing information.

The revised prospectus warns that, if the SEC did object, the company might be required to buy back IPO shares at their selling price for a period of one year. Many analysts believe that the Dutch auction method Google is using for its IPO will result in the shares opening at the highest possible price, which might not be sustainable in regular trading. The prospectus has warned about this so-called "winner's curse" from the first.

The Playboy interview might indeed be seen as hype, as the prospectus details two exaggerations it makes: that Google's Gmail service offers 200 times more storage than others, and that more than 65 million people a day use the search engine. Since the interview was conducted in April, Hotmail and Yahoo have considerably narrowed the gap. And that number of searchers is inflated around 3,000 percent: Its 65 million a month, not a day.

The prospectus does not, however, disclose that Google may have to change the name of its Web-based e-mail service, Gmail. Four other companies have filed competing applications with the U.S. Patent & Trademark Office, all claiming prior use of Gmail.

Bidding is the most important step in the Dutch auction process, an unusual method of pricing IPO shares in which investors name their price by placing bids for a specific number of shares at a specific price. The underwriters use the bids to determine the clearing price, that is, the highest price at which all the shares can be sold. Only those who bid at or above the clearing price get shares.

Despite criticism that Wall Street and investors would have trouble understanding the auction process, Google is moving swiftly -- and it expects investors to do likewise. In the latest update to its S-1 filing, made on Wednesday, the company warned fans to get out their wallets.

Once the SEC declares Google's registration statement effective, giving final approval for the offering, Google can begin to sell its shares. At that point, investors working with nine of the underwriters will have just 24 hours to make deposits into their brokerage accounts to cover their bids or risk having bids cancelled. If the SEC gives the okay on Friday, however, they'll get 72 hours. Investors using one of the remaining brokerages must make their deposits before the actual selling of shares begins.

"However, we and our underwriters may decide to accept successful bids in as little as one hour after the SEC declares the registration statement effective regardless of whether bidders have deposited funds or securities in their brokerage accounts," Google warned. "In this case, as well as all other cases in which notices of acceptance have been sent, successful bidders would be obligated to purchase the shares allocated to them in the allocation process."

Google expects to settle up with investors, exchanging cash for IPO shares, three to four business days after the underwriters send the notices of acceptance to successful bidders.