C.C.
I'm sorry this response is coming so late! I also have 2 boys, ages 4 and 4mos, an a 13yr old daughter, and we just moved to Columbia, MD last summer. You should be able to look it up right on Wikipedia, but it is an amazing family oriented city. It is made up of 5 'neighborhoods' each with its own shopping center, schools, pools, community center, etc. You can also join the Columbia Association which gives you access to their 3 gyms, many pools and discounts at tons of other places and/or events. There is always something going on either at the waterfront(such as Friday night outdoor movies) or at the different neighborhoods. Here's the website for the communtiy: www.columbiaassociation.com
Now for the preschool, my son started at Christ Memorial Christian Preschool at 3, going 2 days a week from 9-noon and he will be going 3 days a week this upcoming school year. The price this past year was $120/month plus a supply fee at the beginning of the year. It is a very small school with only 3 classrooms, one of which is a 5 day class. It is also right on the edge of Columbia, so there was no commute which made me very happy. :) It was perfect for what we were looking for and my son was very happy there. Here is their website: www.cmpcusa.org/old-site/preschool.(hopefully that works, as they're updating it right now).
On the topic of churches, we have attended Cornerstone Community Church for 4 1/2 years now. It is also located in Columbia and is quite small, but it definitely lives up to its name in being a community. Its website is: www.cornerstone-cares.org
Also, one of the sites that my husband and I used when researching areas to move to and later to decide which neighborhood to live in is: www.greatschools.net. Very helpful.
My last suggestion would be to join a MOPS group this upcoming school year. Great support and lots of fun!
I hope this is all very helpful to you and let me know if you would like any more info on anything!
~ C.