Sounds to me like you just need a clustered column chart.
2007 2006
Jan xxxx xxxx
Feb xxxx xxxx
Mar xxxx xxxx
etc.
Note that the top left cell is blank; fight the urge to put a label like
"Month" there, as the blank cell helps Excel interpret your data. Select the
data, run the chart wizard, and choose a clustered column chart or a line
chart in step 1.