DRY ICE: In SA i used both BOC (locations as per SLI-dog's post) and a place called "Dry Ice Supplies" @ 310 Commercial Rd Port Adelaide 5015 (08)84475092
Both can supply pellets (preferable) or 2kg blocks, for the pellets you would want to give them a days notice for more than 5kg.
I generally bought 2-3kg pellets for a session on a cold bugged AMD, or 5-10Kg for a full day of as cold as possible CPU testing.
LN2: BOC with an account (free)
In both cases i have never used Air Liquide as they are only interested in standing order customers, and refuse to sell to one off personal users.
looks like we are lucky in Sydney
they sell to public no worries and cheaper than BOC too
Where did you get the storage tank from (dewar or whatever they call them) for LN2