After a week, here are some stats:

Number of unique devices = 229
Number of visits = 2466

OS version
3.0 => 3
3.1 => 1
3.1.1 => 1
3.1.2 => 26
3.1.3 => 182
3.2 => 15
4.0 => 1

Device type
iPhone => 177
iPad => 15
iPod Touch => 37