User IDs and Sub-keys

[skribe]

Hi:

I'm new to GPG.  I don't understand how user IDs or additional sub-keys work. 
 I've read the manual, the faq and browsed the last few months of archives 
for this list.  Perhaps I missed something.  Perhaps this is a problem with 
my email software (Kmail 2.1).

What I am particulalrly interested in is being able to establish separate 
email IDs using the same key.  For instance, one for skribe and one for the 
name Joe Bloggs.  Currently, when I sign a document the default key (skribe) 
is used, even when I stipulate that the Joe Bloggs ID should be used in the 
email client.  This somewhat cramps my anonymity =).  Do I require separate 
and distinct key-pairs for this or is there a way to do it with the one 
key-pair. 

Additionally, Could someone please direct me to some additional 
documentiation (apart from the manual) as to how to use the IDs and sub-keys, 
to sign and encrypt?

TIA,

skribe
-- 
H:	If a 'GOBLIN (HOB) waylays you,
	Slice him up before he slays you.
	Nothing makes you look a slob
	Like running from a HOB'LIN (GOB).
		-- The Roguelet's ABC