How to fill 'bytea' columns?!?

Hi!

After long scratching and searching, I've come to conclusion that I'd like to
use the 'bytea' type, because it should be able to hold binary data.

But, I've found no doc or FAQ or whatever on that type.

How does one use it? More specifically, how do I get binary values into a 
'bytea'
column using SQL, and how do I get it out?!?

I hope someone can help me out.

TIA,
	Joe