Question:

How can I find the default lead creator in Apex?

Jaxson: 2 weeks ago

In a controller class for a VF form I would like to query the id of the user who was set as the default lead creator in the web-to-lead settings.

How can this be done?

Answer:
Autumn: 2 weeks ago

http://www.salesforce.com/us/developer/docs/api_meta/Content/meta_unsupported_types.htm

Unfortunately Web to lead is not exposed through even metadata API that we can use in apex through WSDL parsing.

An alternative can be maintain a label or custom setting and train the administrator of your organisation to keep custom setting and web to lead setting in sync(May be only Default owner in your case)