Yes
http://www.cupalloys.co.uk/joining-cast-iron-c100028.htmlYou can also braze and soft solder (I think)
Make sure everything is cleaned with a (stainless) wire brush and preheat your parts. Cooling is also important, make sure it is slow. You can also use MIG if you have one, I have used mig before with varying degrees of success.
Type "soldering cast iron" or "welding cast iron" into google and you will have enough reading to keep you going for a few years. Also have a look at
http://www.mig-welding.co.uk/forum/index.phpA british based forum with all types of welding and metal joining, a VERY informative site with tutorials and some sh*t hot welders/fabricators. I thought I could weld until I came accross that site, then I realised I was only sticking bits of metal together.
daz