"Enterprise" software is a market distinction, not a functional class of software, right? Are you asking if the enterprise software market is interesting if you're somehow smart about it?
From my own experience: unless you're doing something really special (and even then it's not guaranteed), it's tough to convince a large firm to license your product if you're a startup or 2, 3 man firm.
The best way, actually, is through the proverbial "back door", i.e. make versions available on the web or downloadable, and get a critical mass of employees within the company to use it.