How to Start Back into Programming

so, I used to be a programmer till year 2002 (Java and C) and have done reasonably complicated stuff (network stacks, credit card and banking software etc)

However, since then, I took a job in another industry to be close to take care of my parents. My personal situation is likely to change over next 6-12 months and I will be able to get to programing (if I can get a job)

I was wondering how can I come upto speed to become a good programer 15 years later? what things I need to learn?

Should I go back to school? or are there web resources or books that I should read?