I have a worksheet for each month, and reference my ending balances in the
previous month in the current month. I now want to create a summary
worksheet and need to reference the current months balances. I'd like to
create a reference whereby I can replace the "month" portion of the name,
using a cell on the summary sheet.

example: tab names are AB_nov_2009, AB_dec_2009 etc.
my reference would be: =AB_nov_2009!b4

I'd like to use a cell to change the nov to dec without having to go to each
cell and change the month.

Possible?