Atmel Markings 58BL W 9H0336E
Possibly ...

Identifying parts got a whole lot harder once the parts became too small to hold the whole part number...

The significant part of the marking will be 58BL. 0336 will be the date code (week 36, 2003)

Now searching the obvious place for ATMEL 58BL yields a lot of rubbish, and this supplier in Poland whose listing contains: 


  us AT25080-SSHL Atmel SO8 SMD Pbf;ATMEL;58BL


which gives us a possible clue. AT25080 looks like a real part number, and the first search hit for Atmel AT25080 is this datasheet for a 1kbyte EEPROM with SPI interface in a SO8 package.

But now you're going to tell me it's in a 40-pin package and couldn't possibly be this part...

EDIT : a little more digging on Atmel's website here shows a newer datasheet for the 25080B, and this one shows the product markings : page 14 shows the code 58BL.

I'm going to guess it's probably a 25080A from the date code; unfortunately that one's datasheet again doesn't show the markings.