Concatenate Cells And Delete Duplicates

I have an excel 2007 spreadsheet that lists
items on multiple rows for the same customer.

Each sheet will list anywhere from 25 to 100 individual customers.

I need to identify the duplicates, concatenate
the "Items" to a single cell on the first row, and
delete the duplicate rows. eg:

Cust #| Item
1 | A
1 | B
1 | C
2 | B
2 | E
3 | A
3 | C
3 | E

The result should look like:

Cust# | New Item
1 | A, B, C
2 | B, E
3 | A, C, E