Thanks Chrissy2u,
Very handy document. Is this the document they are using now, do you know? I'm assuming it's current, but thought I'd double check.

In particular, worthy of note to my personal situation is the statement:
"An employed person works under the instructions of someone else and is part and parcel of the organisational task force of the person who gives the orders".
I'm asking the auslanderbehorde and the arbeitsamt if I can work for an agency or personnel company, with an employment contract upto Dec 2009... Based on this statement above, it sounds like I'd have to work for an employer direct. It seems a bit of a grey area... The agency does have it's own offices and takes in work to do in house, as well as placing people in the offices of their clients.
I'm Australian and I know the rules are different for non-EU people. A few UK people are working through agencies, but for Aussies, I'm not sure of the situation. Any thoughts?
Thanks again for the info.
EDIT : "Normally the basic rule applies: if you are an employee, you do not work freelance" Since I wouldn't be a freelance or writing invoices, would this mean I get around this potential issue? hmmmm..