VickyLynn~
I've made this trip many times over the last 15 years with my kids at various ages. I live in NYC but am from San Diego and most of my family is still there so we make the 6 hour flight at least once a year. bbkimberly's right, at take off and landing their little ears are more suseptable to the pressure so it's best to keep them distracted at that time. Finger snacks work good at that time since the chewing will help equilize the pressure. I also brought a walkman with their favorite music. Try to avoid toys with small pieces or you will be bending over the whole flight to retreave them from the floor

Etch a sketch or toys like that are great cause they can draw without pens or crayons. On our last trip, DD Lici was 2 and was happy with her favorite stuffed animal and her blanket and wound up sleeping for 3 hours. Have a great time in San Diego, it's beautiful there and if you have time, be sure to go to the Zoo & or the Wild Animal Park as it's the best in country.
Hugs ....