You may get a list of keys with the keys property:
In [20]: d=OrderedDict((("fruit", "banana"), ("drinks", 'water'), ("animal", "cat")))
In [21]: d.keys().index('animal')
Out[21]: 2
Better performance could be achieved with the use of iterkeys() though.
For those using Python 3:
>>> list(d.keys()).index('animal')
2