You need to get information from your website into Salesforce, especially for Leads for new clients.
If you are on full WordPress you can use Gravity Forms for Salesforce plugin – it is a free plugin to Gravity Forms, and it can be used on all versions of Salesforce – with Web to Lead for the lower end versions of Salesforce, and Web to Anything, via the API with higher end versions of Salesforce.
If you are not using Gravity Forms, you can use the WordPress-to-lead plugin.
Wufoo Forms is another app that does Salesforce Integration, but not really very well. About the only time you would use Wufoo integration with Salesforce is if you were a NFP with a WordPress.com site. Wufoo is a great option for nice forms for a WordPress.com site (see my previous post on using Wufoo with WordPress.com), but as there are so many other options for full WordPress, I would not use Wufoo except for on WordPress.com.