Is there an API to access the results returned by the Keyword Tool in Google Adwords?
Also, is there a site that provides an API to verify if a domain is taken?
This question appears to be off-topic. The users who voted to close gave this specific reason:
The Adwords API lets you access the Adwords Keyword Tool.
For domain name availability checks, there is a now closed question on Stack Overflow: Finding if domain name is already registered?
Let me know if you still miss something.