Ploting Date

Oi, I'm having trouble ploting some values vs date with matplotlib.

I get the data from an SQL server using the _mssql module

after the query I tried populating the list using:

[code]
xls = []
yls = []

for row in conn:
  xls.append(row['Ia'])
  yls.append(row['tiempo'])
[/code]

The row['tiempo'] is datetime in the SQL table so I get yls filled
with datetime objects

At first I tried displaying it in an YYYYMMDDhhmm format using
[code]
temp = row['tiempo']
temp = str(temp.year) + '-' + str(temp.month) + '-' + str(temp.hour)
+'-' + str(temp.minute)
temp = int(temp)
yls.append(temp)
[/code]

but after seeing that matplotlib by default uses an exponential
notation y then realized that the scale would be off.
If I use date2num() it displays numbers not dates.

Basically I would like to plot the data against dates, with the
ability to autoscale from a minutes view to a month view at least. The
data set is failry large, at least 1 year of data from 5 minutes apart
measurements.

Any pointers in the right direction? Can I plot dates without
converting them to a number? If not could the numbers be linked to
back to the date and the date be displayed in the axis instead of the
numbers?

Thanks for your time.