Read anything by Lee and/or Lyman bullet mold companies. Lyman has a fantastic manual called the: Cast Bullet Handbook. It contains cast bullet reloading data too.
And not to be a jerk, but if you're going to play with fire, melt hot lead, calculate tin/antimony additions, and make bullets you should immerse yourself in the process first.
You'll learn so much more and retain so much more if you seek and absorb the knowledge for yourself. Once you dive in and have questions on tweaking things, there are oodles of guys here reading and willing to help.
There is some wizardry and artistry and science that goes into making nice bullets. It's like Christmas every time you open the mold.
I use the Lee 6 cavity 230gr Truncated Cone. Bullets are cast from strait wheel weights . If I remember correctly I had trouble finding load data for this shape bullet so I used mid range 230gr lead round nose charge data and made dummy rounds to determine what the longest OAL is before the bullet touches the rifling or the round is too long for the magazine. I have had 100% success using this method in reloading for my 1911 and UZI carbine in .45 acp. For some reason I can't get this load to work in my kahr CW 45 actually I have had problems reloading for the CW 45 in general but that's another story.
Question:
Is there a particular firearm you will use the 45ACP bullets in?
Have you done ANY reloading before?
Personally, I was reloading several years before I did cast. My first cast bullets were actually round balls for a muzzle loader.
I went to 9mm next.
If I did it all over again, I'd have gone to a revolver bullet (45LC or 38spl) next instead of the 9mm.
As mentioned ...Lyman.. read what you can, great resource even the new manual contains good nfo. they also make good casting equipment, tools that you need. Everyone has their choice of molds,and I'm sure others here will chime in. I have to say the MiHec brass molds are great, he has some awesome molds for the 45. Also check the out Castboolit site: http://castboolits.gunloads.com/forum.php
When I started it was with the .44 mag and "Keith" style bullets, H&G molds, .38 spl SWC, WC, .45ACP
Castboolits has a lot of casters on there,you can get lead, Linotype lead etc.. from time to time.
MiHec does group buys on there you may have to wait a while to get the molds, but well worth the wait..
And as iH8DemLibz says playing with fire and melting hot lead.
you will learn hardness, mixtures to get you the desired hardness, but upmost and formost safety, when you have molten lead
and you do things to molten lead...