subdomain

[luke]

hi, i currently example.com from godaddy.com working with a couple of
subdomains, namely, www. mail. etc...
all through godaddy's dns. i have a dynamic ip address, so i can't run my
own dns for example.com
i want to add another subdomain, blah.example.com and setup
www.blah.example.com and a few other subdomains
for blah.example.com. the primary dns is still going to have to be through
godaddy, but if i add an a record for blah
pointing to the same ip address as example.com will requests for
blah2.blah.example.com query the godaddy's name
server or the one running on my machine? currently, www. mail. etc. are
CNAME records at godaddy's dns. hope this
makes sense. i'm new to dns and don't really have the terminology down, but
i'm reading lots of online docs and picking
it up slowly but surely. thanks
luke