While some might guess that an armchair millionaire is someone who can answer all the questions on Regis Philbin's hit TV show, ArmchairMillionaire.com is actually a Web site frequented by tens of thousands of ordinary investors. In this investment guide based on the site's philosophy, Schiff and Gerlach, two of the Web site's principals, assert that investing intelligently requires little more than common sense, discipline, patience and a goal-oriented mentality. Most members of Armchair's virtual community are neither excessively frugal nor do they have perfect credit reports, the authors maintain. Learning about the stock market, avoiding brokers who insist they have the answers and controlling debt are the keys to financial success, they say. In fact, the heart of this program is based on five simple steps max out tax-deferred savings plans, set aside money for yourself before paying your creditors, invest automatically, use the ""armchair"" investing policy and start today. Schiff and Gerlach's mix of anecdotes, homespun advice and investment strategies will be familiar to those who frequent the site. Uninitiated readers, on the other hand, will have to suffer through what is essentially an extensive ad campaign for the Web site to glean the book's practical benefits. (Apr.) Forecast: Given the popularity of ArmchairMillionaire.com, fans of the authors may well push this book onto some bestseller lists. Ultimately, though, Schiff and Gerlach don't offer much that's sufficiently new or insightful to distinguish their book from the many others on the overcrowded investment shelves, so the book's long-term prospects may fade.