I just released a new plugin that is an add-on for Gravity Form which allows leads generated in Gravity Forms to be fed into HubSpot.  The Gravity Forms HubSpot add-on let’s you use the HubSpot Lead API to send your Gravity Forms based landing page leads directly to HubSpot. All you need to do is add one setting and check a box when configuring your forms.  All your form entries will then be added to HubSpot from now on. Integrating with HubSpot has never been so simple.

You can grab the plugin right here:

http://wordpress.org/extend/plugins/hubspot-for-gravity-forms/