1. Does Snappy have support for video recording on the 3gs?

Yes.  As of version 2.0

2. Why am I getting a “Sorry, no record of payment for this device could be found” alert message?

Because Snappy can not verify that you have paid for the app.  It is possible you have somehow downloaded a cracked version of Snappy that does not work properly.  Please pay and download a version from the cydia store (bigboss repo).  If you are unaware that you downloaded a cracked version, it is likely because you have added a repository that contains it.  Please remove your added repositories from Cydia and the correct one from bigboss should show up.

3. How do I launch Snappy?

As of version 2.1, Snappy is integrated with libactivator, so any of the methods available to libactivator can be used.  (Currently, shake does not work).  Launch the Settings application and go to Activator to assign activation methods.  Also, there is now a springboard icon for the application.  If you would like to hide the icon, please use SBSettings to do so.

4. I have already purchased Snappy for one of my phones, can I get it for my other phone without having to pay again?

Yes.  This is a general feature offered by the Cydia app store.  On your other phone, click "Purchase" to buy Snappy.  Log in with the same Google or Facebook id that you used when you made the original purchase.  Cydia will recognize your new phone and ask if you want to add it to your account.  Agree.  Now Cydia will recognize that you paid for Snappy (as well as other apps) and the "Install" button will be available without having to pay again. 

5. Can Snappy launch a different camera application like Snapture instead of the native one?

Snappy does not launch the native camera application, it recreates its functionality and makes it available instantly.  Therefore it's not possible to swap in another camera application.  However, I am happy to consider feature requests that would enhance Snappy's functionality.

6. Can you add video functionality for the 2G and 3G devices?

I do not have plans to add video capability for non-3GS devices at this time.

7. I am getting libactivator conflict errors during install and Snappy won’t launch.  What’s the deal?

Probably because you have previously installed the libactivator package from a repository that renamed the package id (com.beyoip.libactivator).  This is not the original package.  Please launch Cydia and remove all versions of libactivator, Snappy, and packages that depends on them. Now reinstall Snappy (and from the *correct* repository, install your other packages that depend on libactivator).