I've gone back and forth on doing official 'preschool time' and just doing fun activities with the kids. It seems like a little bit of each is the perfect thing right now.
I've come across some really great blogs and sites in the last few weeks from former and current educators/moms that have reminded me how much I really love child development and this fun preschool age. Some of the sites are great because they have super printable materials for preschool themes that make a great starting place for planning the more formal preschool time. Others I love because they are full of fun ideas to play with your kids and help them learn through play.
My favorite learning through play sites:
Homeschool Creations has some great activities. We've been using the Transportation theme unit printables and having fun adding our own games/songs/books/poems/activities that are transportation related. More great printables too at Confessions of a Homeschooler (She has a very thorough collection of Alphabet printables and activities that I think I'll reference often). And, some more fun things at 1+1+1=1 .
And a few more that seem pretty cool so far: