To subscribe, clients must download the prospectus from which they obtain a tracking number which validates their subscription. Perhaps the most novel way to get into IPOs is through a firm without individual retail clients, really a middleman in the distribution system. Then you can give an indication of interest and, if you let your offer stand, your stock will be delivered to your own broker and you'll settle with that broker. Many tech IPOs are fuzzy and you need an idea of what the firm will be in six months. What the company says about itself is not necessarily the reality of its situation.
Professional analysts have the edge here.
There are cases where management loots firms as they go into bankruptcy. You want to know who you are dealing with. Finally, and this is the toughest thing, you want to know if an IPO is properly priced. But in IPOs, especially tech and e-business issues are very hard to price. In a market where new issues are sold for valuations that have nothing to do with earnings, the new metrics of hot stocks depend on market price to Web hits and such.