Where, oh where has my Sharepoint feature gone...

Yes, another newbie to Sharepoint post; but it may help the others out there who are working through labs and exercises and not getting the "expected" results.

If after you have deployed your new feature (e.g., workflow, web part, etc) you do not have it listed as an available content type, it might have been added successfully but not activated. 

To activate a feature go to the Site Settings:

Select Site collection features option from the Site Collection Administration section.

A list of loaded features is presented with the option of activating and deactivating.