All the information you could possibly ever need......you will find right here!
Take it from someone who knows! I am just finishing my first batch of plugs and were it not without the help of the builders on this site, they would not be coming out nearly as well as they are.
Better still, if you get in a tough spot or need to ask any question at all, simply post and someone will have the answer you are looking for in no time.
A small lathe would be a good place to start....I got mine used from Bassmaster for about $50.00 and it works great. The same model lathe, a Grizzly can be found new at their website Grizzly.com. Its a small tabletop model and sells new for I think about $150.00 maybe a little more. Use the search mode here on the site and you can find all the information you need.....good luck MotorFish and welcome to the wonderful world of plug building!
Oh, almost forgot, if you are serious about getting into plug building, you will want to attend "Plug Night II" at MSBA on August 25th in Braintree. Everything to do with plugs from building them to fishing them...it is a blast! Hope to see you there.