In a recent article, on Chronicle Vitae, Robert Jenkins posed the question "Can a Community College Job Be a 'Steppingstone'?"
The short answer is no. A community college job is not a step to your tenured job at a four year college.
On the other hand, community colleges make up about 40 percent of the available faculty jobs out there (some of them tenured jobs) and it would not be wise to overlook them in your quest for full-time employment.
For more on working at community colleges, check out Jenkins' article.
For another viewpoint on the issue, check out this Monkees video: Steppin' Stone.