Summertime was played on the "American top 40 with Ryan Seacrest" this week. I don't think it was officially in the top 40 because the song before it was #19 and the song after it was #18, and they called it this week's "breakout". So maybe it'll officially be on the countdown next week. Click here to listen to guest host Steve Carroll introducing the song.
Update: 9:01pm - Thanks to the person who left a comment that "Summertime" was this week's "Sure Shot" on the Rick Dees Weekly Top 40 (I didn't know he was still doing a countdown!). Anyway, you can listen to him playing the song here (it's within the first minute, this link will probably expire by next week).