Hi,

I did it the following way:

DISTANCE/(HOUR(X) + (MINUTE(X)*100/60)/100

1. DISTANCE is the cell containing your travelled distance
2. you devide the distance by the following:

X is the cell containing the time you filled
so:
(HOUR(X) + (MINUTE(X)*100/60)/100

I use it in the sheet I have loaded in my PDA when I go on vacation, I have include fuel consumption and time going form A - B thus calculating also the mean speed, etc.

I hope it helps,

Hans