SaaS marketing & customer acquisition

I found these links which I found being very useful: 7 Non-Obvious SaaS Startup Lessons From HubSpot http://onstartups.com/tabid/3339/bid/13320/SaaS-101-7-Simple...

HootSuite: A software-as-a-service success story http://thenextweb.com/apps/2011/07/06/hootsuite-a-software-a...

For niche markets, I recommend reading "Start Small Stay Small" by Rob Walling. You'll have to keep a critical eye while reading, but it will give you a basic canvas to iterate on.