I heard somewhere that the leads of common electronic components (resistors, capacitors, transistors etc), such as you might buy from Dick Smith Electronics are tinned with a lead based compound. Is this correct? Any help with this query would be appreciated.
Solder is a tin-lead alloy (unless you use specifically lead-free solders), and that is what is (generally) used for tinning, so the answer is yes. You should assume any solder contains lead and use appropriate precautions.
DSE stores may still have stocks of components, but they're in a big mess. A few days ago I needed a rectifier and a 470uF cap. I didn't need specific types, which is just as well... only about half of the trays with rectifier labels had anything in them (some were "cross contaminated" with completely unrelated components), and the 470uF tray was empty. I ended up grabbing a 680uF from a tray chock full of them, but that value isn't even in their catalogue any more! Of course the chick behind the counter spent 30 seconds peering at the wrong page, wondering why the little blue cylindrical thing with two legs didn't match any of the photos on it...
This was just a quick trip to get a couple of things but it ended up being extremely frustrating. I wish Jaycar was closer than it is. :)