The steps for this are below:
§ Complete the publishing wizard (using the SharePoint option) and publish the form to a shared location
§ Launch the SharePoint Central Admin page
§ Select Application Management
§ From the InfoPath Forms Services section select Manage Form Templates
§ Click Upload Form Template
§ Click the Browse button and navigate to the shared location where you published the form
§ Highlight the form and click Open
§ Click Upload
§ Assuming the template uploads successfully, you will be returned to the Manage Form Templates page. Click on the uploaded template and select Activate to a Site Collection
§ If the Site Collection box has the correct site, click OK. If not, click the site and you will be able to change to the correct site.
§ Once the activation has completed, you can now associate the form with a form/document library
§ Navigate to/Create a form or document library
§ From the Settings button, choose Form (Document) Library Settings
§ Select Advanced Settings
§ For “Allow Management of Content Types” choose Yes and click OK
§ You should now see a new section called Content Types – click “Add from existing site content types”
§ Drop down the box and choose Microsoft Office InfoPath
§ From the “Available Site Content Types”, highlight the form you activated, click Add and then click OKMail me your comments and suggestions.
This is a very useful post, I also had a problem with a site feature, the following feature was disabled and i had to enable this to get the procedure you described working.
"Office SharePoint Server Enterprise Site features -
Features such as the business data catalog, forms services, and Excel Services, included in the Office SharePoint Server Enterprise License"
Glad it helped you ... :)