Sounds easy enough. Assuming your data is something like:

(col a) (col b)
Header1 values
a 73
b 84
c 31
a 14
b 24
b 88
c 46
c 89
b 22
d 67
d 48
c 75
d 67
a 64
d 92

then this:

Sub test()
Cells.Sort _
key1:=Range("A2"), Order1:=xlAscending, _
Header:=xlYes, _
OrderCustom:=1, _
MatchCase:=False, _
Orientation:=xlTopToBottom, _
DataOption1:=xlSortNormal
Cells.Subtotal _
GroupBy:=1, _
Function:=xlSum, _
TotalList:=Array(2), _
Replace:=True, _
PageBreaks:=False, _
SummaryBelowData:=True
End Sub

would produce:

Header1 header2
a 73
a 14
a 64
a Total 151
b 84
b 24
b 88
b 22
b Total 218
c 31
c 46
c 89
c 75
c Total 241
d 67
d 48
d 67
d 92
d Total 274

Grand Total 884