Hi E. - I don't know anything about the Wheaton Park District preschool, but since you also asked for other suggestions for this area ...
M oldest two kids, ages 3 and 5, attend Carol Stream Christian Academy, which is a preschool through elementary school at Schmale and North Ave. in Carol Stream. My 3-year-old son is in his first year of preschool there, and my 5-year-old daughter, who is now in kindergarten there, has attended since she was in 3-year-old preschool. It is an amazing school, and I love the continuity of the same kids growing up together beginning when they are 3. I don't know of any other preschool in the area that continues on to kindergarten and elementary school. We have families that come from all over Chicagoland to send their kids there - one even lives in Indiana and drives over an hour each way. My daughter learned to read there when she was in 3-year-old preschool and now, in kindergarten, reads around a second or third grade level. My 3-year-old is learning to read this year, just like his sister did there at his age.
I can't say enough praise about the school - the teachers, administration, and academics all combine to make it a place of excellence, or I wouldn't send my children there. You can see from their website (www.carolstream-christianacademy.com) a little more of what the school is about if you are interested, and I'd also be happy to tell you more about it. Their website is badly in need of updating though (which I have volunteered to do with their "webmaster"), so, on that issue, I'd have to say don't judge a book by its cover!