E.H.
you've already gotten some great answers. just thought i'd add my experience:) i currently homeschool my oldest in 1st grade, one in pre k, and i also have a 2 yo and a breastfeeding 4 month old:) much of our day is spent learning how to play nicely with each other-take turns- be a good big brother and such. when the little ones take naps we do school work. it takes very little time to actually do any curriculum at this age and when we are done we read together or look up stuff on the computer or play learning games. it really should just be fun. also we try to do the same "routine" everyday albeit a very loose routine, but they always know what to expect at certain times of the day. if you set up a basic routine at the beginning of the year by the time baby comes your little ones will already know how their day will go regardless of new baby. also it's pretty difficult to "mess up" preschool and i bet you'll be surprised at how much they learn without much effort at all. also target has great workbooks in their $1 section right now. good luck and congrats!