Going for a PhD after working in industry?

After working as an electrical engineer for a few years, I'm thinking of going back to school to get a Phd.

Some major things that are still making me hesitate are: 1. Funding? Should I even care about it before I even get an offer? I know I can't afford to fund my way through the course. 2. Letters of recommendation. Is it okay(or advisable) to ask more senior colleagues who know me or my boss to write something? People often recommend university professors to write letters but I wasn't too close with my university professors.

I'm also thinking of contacting some professors I want to work with beforehand to gauge whether I have a chance at all to work under them.