What do you suggest listing for my employment history?

I am beginning to search for a job after six years as being a stay-at-home mom and am working on updating my resume. I have four years of volunteer work on an Executive level during that period, so I am not too worried about that.

What I am concerned about is a lapse of three years between the last two paying jobs I held prior to staying at home. I worked at one company Feb 2002 – Feb 2005. Before that, I worked at another company Aug 1998 – Aug 1999.

Should I leave off the second company because it was so long ago? (Including it would also raise the question of why I moved across the country for a year and I really had no reason. It was an impulsive and unwise move.) I also have related experience for 2–3 years in the early 90s, but I doubt that is relevant at this point.

The break is because I went back to college and dedicated my time to completing my degree once and for all. I did hold part-time jobs, but nothing relevant to my career aspirations. (Am I require to list those?)

Also, do I need to differentiate between volunteer and paid positions? My intention is not to imply that I was paid when I wasn’t – it is just a formatting question.
Any advice?