A quick check with Google came up with this... along with other products...http://www.digitalintelligence.com/cart/html/1.8-Inch-Laptop-Hard-Drive-Adapter.html
I would check with Sony to make sure you're not voiding the warranty (assuming you still have one) by taking the thing apart. Better safe than sorry.
Virtually no desktop computer known to man will be able to accept a 1.8 inch drive without some sort of adapter. At least the one I sent you a link to was cheap... another I saw was nearly $100.