The following works for me.
>>>> xticks(arange(len(data)), date, rotation=30, size='small')
Yes, and you can change the rotation of the existing ticks with
from pylab import figure, show
fig = figure()
ax = fig.add_subplot(111)
ax.plot([1,2,3])
labels = ax.get_xticklabels()
for label in labels:
label.set_rotation(30)
show()