I recently dropped into RS Components in Archerfield QLD for a Rotary switch for my AV Bay. The guy I spoke to had attended a launch of our in the past and was great to deal with. He has given me a bunch of their 2" thick catalogues (bible paper thickness!) to pass around.

These guys are located all round Australia and stock all types of bits and pieces.

Check out their website here:
http://australia.rs-online.com/web/

I have also used these guys in the past for electronics components, however never for rocketry (yet):
http://au.farnell.com/

RS are a very good supply on electronics, but can be very expensive for some items.

For hobby stuff:
http://www.futurlec.com.au
http://www.sparkfun.com
http://www.dontronics.com.au
and of course
http://www.altronics.com.au
http://www.jaycar.com.au

For better pricing (particularly on QTY>10)
http://www.digi-key.com
http://www.mouser.com
We order at least once a month from these guys, have wholesale accounts etc.., happy add your stuff and save you some shipping.

PK

I have been buying stuff from these guys recently, their range isn't as large as some of the bigger suppliers, but their prices are good http://www.photonage.com.au/

Farnell, like RS is expensive, but sometimes convenient. All their online orders are now free shipping, regardless of cost of order.

http://au.farnell.com/
just saw this in the first post - sorry!

Also for small reels of SMT parts etc, try Soanar Plus. They own electus/jaycar and use the same part numbers but have extra reels/parts etc at the more professional end of the spectrum, without the trinket junk Jaycar sells. Soanar's website is a dog though. Call them up and get them to send you a paper catalogue, it's worth the effort if you are doing small runs locally.

https://www.soanarplus.com/default.jsp?xcid=1

I found these guys today, they supply a lot of the sparkfun stuff, but they are based in Australia. They have some very cool stuff!

http://www.littlebirdelectronics.com/