Even before they are ready to launch, Sony is warning that they may have to reduce shipments of the PlayStation 3. Potentially resulting in only half the number of available units as they initially stated, Sony is pointing the finger at production woes as the cause:

Due to the fact that mass production of Sony PlayStation 3 (PS3) game console has not yet started, SCEI is likely to reduce the targeted number of PS3s to be shipped from 4 million to 2 million units in 2006. This will catalyze shortages of the game machine across the world and may allow Sony’s rivals, particularly Microsoft and Nintendo, to sell more consoles during the season later this year.
Other reasons include lack of availability of some components, such as blue laser diodes needed for the BluRay optical drives. They still plan to have 6 million PS3's on market before next March. In the short run, this could potentially mean even more price hiking at the retail end, with stores looking to capitalize on the short supply. Of course, this won't affect those who want a PS3 but don't mind waiting a few months.