I DON'T have an iPhone, but I do have a Windows Mobile smartphone (AT&T Tilt). iDrive indexed all 1400 contacts (over 30% of them have two or more numbers) with no problem. Way cool in my book.
'03 X5 4.4i Blue/Tan
'06 E90 330Xi 6MT Sparkling Graphite/Terra
'08 E92 M3 6MT Jerez/Speed Cloth <-- Evil Twin