Import or Programmatically create nodes with Videos I'm working on a new drupal site which I need to migrate from an existing non-drupal site. I need to be able to import the old blog posts as Article nodes (either through some standard import mechanism or I can write some php to programmatically create the nodes).

However, I'm not sure how to handle creating Image and Video data in a node, especially with the need for transcoding video after creation of the node. So, two questions:

1) How can I programmatically create nodes with binary Image and Video data?

2) When I do create a node with Video data, will the post-create transcoding job be started? I'm using Zencoder to do my transcoding.

I am not using the local filesystem for drupal, I'm storing all of my files in Rackspace Cloud Files, however, I can handle it if I need to use the local filesystem temporarily during import and then manually move things over to Cloud Files. This is only a one-time event.
Your best bet is to use the Migrate module. It's got a kinda steep learning curve but plenty of documentation available.

The Migrate Extras module provides integration with the Media module, which could help with the video field specifically.