TDK has announced that they've started shipping their 25GB recordable and rewritable Blu-ray Disc media. Here's part of their press release:

TDK, a world leader in digital recording solutions, today announced that it has begun shipping 25GB recordable and rewritable Blu-ray Disc media to retailers nationwide. A pioneer of blue laser recording technology and founding member of the Blu-ray Disc Association, TDK is the first to market with bare Blu-ray Disc media. Retail pricing is set at $19.99 for a 25GB BD-R (recordable), $24.99 for a 25GB BD-RE (rewritable). In addition, TDK will ship 50GB Blu-ray Disc media later this year with retail pricing set at $47.99 for a 50GB BD-R (recordable) and $59.99 for a 50GB BD-RE (rewritable).

The revolutionary single-sided discs are bare, cartridge-free media. The 25GB products are single layer whereas the 50GB products have a dual layer recording material structure. TDK first shipped mass production samples in December 2005, and with the subsequent issuance of the relevant license, the company immediately commenced full force manufacturing.
TDK's press release also mentions that they've created 100GB, quad-layer Blu-ray Disc prototypes and have pushed recording speeds to 216Mbps (6x). The company is also in the process of developing the world's first 200GB Blu-ray Disc prototype. If you'd like to read more, TDK's entire press release can be found here.