Yes, that's the whole point of browser-enabled forms. It's a function only of InfoPath 2007, and it requires MOSS Enterprise (includes Forms Services) or MOSS Standard plus Forms Server (separately-installed product). It's most typical for organizations to use MOSS Enterprise for full browser-enabled forms integration.
That is the only way to do it with SharePoint. The only other method for browser-enabling that I know if is built by the folks who run this forum - Qdabra.com.
If your forms are not browser-enabled, then each user must have IP07.