You can learn a lot of class-taught PM skills by checking course requirements for a Masters-level IT or management program. MIT, to name one school, provides many of their course materials for download and study. Most include teacher notes, talks, or presentations for self-study and point to other resources.
MIT OpenCourseWare: http://mitsloan.mit.edu/academic/open-courseware.php
Software program managers need to understand people, development methods, scheduling, and negotiation, so expect to study at least those four areas. Building a range of skills helps you step into different roles as-needed, from planning to coding to testing. (Writing well also helps, so find an editor or colleague to review your work.)
To further develop your practical skills, look for an open-source project or local business start-up that needs help. It's an important resume addition for you and they'll usually take enthusiasm over formal PM certification.