Is it possible to create a product on amazon programmatically using the api? I would ideally like to create a product using the spree commerce CMS and at the end of the day sync products between the CMS and an online amazon store.
On the Amazon side, you can create products using the Amazon Marketplace Web Service, in particular the feeds API (code samples here).
On the Spree side, you can make this happen by either writing an extension, or by using Spree's middleware product (Wombat) and creating a custom integration for it.
Spree is pushing hard for more integrations that have broad appeal, and syncing with Amazon MWS definitely fits the bill, so you may be able to contact them and get some help doing these things (my company is a Spree partner, and we're currently working on an open source integration to a popular CRM tool for another seller).