Run model validation before saving a model instance
How to validate your model at save using the pre_save signal. from http://groups.google.com/group/django-developers/browse_thread/thread/eb2f760e4c8d7911/482d8fd36fba4596?hl=en&lnk=gst&q=problem+with+Model.objects.create#482d8fd36fba4596
- save
 - clean
 - pre_save
 - signals
 - validate
 - full-clean
 - full_clean