You can distribute a FormsCentral PDF for users to fill out on an iPad using Adobe Reader. There are a few options for how you could do this.
Option 1: Save the form as a "Submission enabled" PDF from FormsCentral - for multiple users to be able to fill out he form you would have to create and copies on the iPad, this response from Genevieve describes the process you could use: http://forums.adobe.com/message/5338420#5338420
Option 2: Save the form from FormsCentral as a PDF without a Submit button, it would not send data to FormsCentral, instead you would add your own submit button using the "Email Submit" method that would email either the form data, or the entire PDF back to you. Using this method you would create a Submit button that did two things - Email the PDF/data, and clear the form for the next user. Each time a user fills it out and clicks "Submit" a new mail message would be created and queued with the form. Once you had an active internet connection again
How to create a "Clear form" (reset) button: http://tv.adobe.com/watch/acrobat-x-tips-tricks/quick-tip-how-to-add-a-reset-button-to-a-f orm/
How to create an Email Submit button: http://www.youtube.com/watch?v=Jql1wp5Gofs
(Note that you can do both of the above on the same button)
How to edit a FormsCentral PDF in Acrobat: http://forums.adobe.com/docs/DOC-3661