Those smart people at BNET UK have published a great article listing 5 useful business applications for each of the iPhone, Android and Ovi (Nokia) platforms.
I haven't downloaded any for my iPhone yet, but the car mileage app looks particularly helpful since I can offset the cost of any petrol used for business - but need to keep track of those trips.
Anyway, here are the links to the lists for each platform. Choose the one(s) appropriate to your phone(s).
5 business apps for iPhone owners
5 business apps for owners of smartphones using Android
5 business apps for Nokia owners
