We have a public preschool attached to our school district here, and my daughter is 3 and a half, we went ot the screening and she passed with flying colors, BUT, that counted against her for getting into the preschool - the kids who were less advanced, family or economically disadvantaged, and older, got prescedence. So whether we like it or not, we are waiting till she is 4 and a half for her to go to preschool. I really was looking forward to the social interaction for her, since I stay home, and most other moms in out tiny town work - she doesn't have many play dates or friends her won age she gets to spend much time with.
That said, she is doing fine developmentally, physically and mentally. She is starting to read, and do simple adding and subtraction, she knows all her letters, Capital and lowercase, and the sounds they all make, can count to 20, knows all her colors and shapes, and is learning more day after day. You can teach them those things fine at home, BUT I believe preschool is essential to learing to get along in the school structure and play well with others, etc.
I am looking forward to her going next year, and we talk about it alot, so it won't be scary or a big surprise when it is time.
As for "resources" your own home and everything in it can be a teaching tool! All her little books, anything you can get from the library, do crafts with her, let her explore and do arts/crafts herself, let her help put away dishes, fold laundry ( mathcing socks, folding wash cloths and towels, sorting clothes into whites, brights and darks). We do love our BOB books http://bobbooks.com/ she read the first two of the first set to me all by herself the other day!!! We have learned alot from placemats - found mostly at Walmart - she learned colors, shapes, numbers and letters from placemats, after she was done eating and mom and dad were still eating, we whould talk about her placemats with her. I have a craft room in the basement, and she has her own corner in there, with paints, markers, clay, crayons, stickers, safety scissors....we work together and independantly, and she loves it!
She also LOVES to help me Bake and cook, shich are actually math and science skills, counting, measuring, mixing, following a recipe ( a formula ) to make something!
Good Luck!
Jess