Josh,
In 9.3 the sequence would be to listen out for the onCreateFeature event in the IEditorEvents Interface. This gives you a handle on the the feature you just drew and through this you can gain access to the attributes of the feature which you update.
If you are using Domains on fields then you'll want to access and read those values into your combobox on your form, check out the IDomain Interface.
If you are using 10 it maybe different as Templates now exist, not sure how they complicate things.
Duncan