Hi,
It's there (for me) on the Domestic Shipping Services drop-down list (between USPS First Class and Parcel) for both the Flat and Calculated, as US Postal Service Media Mail. I just checked the lister and verified it still is on the list.
I used Media almost exclusively for listing books, reference material, and software media from last fall through the spring. It's also availabe for PayPal Click-n-Ship with the electronic Delivery Confirmation tracking (for only 18 cents, last I checked).
Danno