There are 10 levels in the programming skill. The programming skill will allow your sim to make virues, games, apps, game mods, take temporary tech jobs, hack into banking systems and to hack work/school experience.
To get started with the programming skill, buy a computer or purchase the programming books from a bookshelf.
The easiest way to get this skill maxed is to join the Tech Guru career and work on both the skill and maxing out the job. It took me about 2 hours (real world) to get a sim maxed out but he was also working on the gaming skill at the same time.