After having lots of issues getting the website to transfer data from our website to ZohoCRM using web-to-lead, we created a plugin to do this, and have released it so everyone can streamline this integration. 

The plugin uses the Zoho API, so you don't need to muck about generating the web-to-lead forms. There is a graphical set-up in the plugin that allows you to map your website form fields to your Zoho Fields. You'll be up and running in 5 minutes.

Video and more info at http://helpforwp.com/plugins/gravity-forms-to-zoho-crm/

If you like that, you may also like the plugin that parses the google cookie and ads that tracking info to each lead (search engine used, search term entered) -  http://helpforwp.com/plugins/google-analytics-tracking-for-forms/

And there's free WP Video training materials too ... http://helpforwp.com/

Jon