I have created a developer account in salesforce. But now I need to create some logic that uses some custom objects that someone create in the company's salesforce.
Should I create a developer account in the company's salesforce?
Or should I replicate everything to my developer account?
Or...?
And how do I do it or where can I learn how to do it?
I need to use objects created in production environment .
You should get the custom objects installed in your developer edition.This can be done in many ways like using an unmanaged package which you can create in your company's salesforce.
Your company must be having a specific edition of salesforce like Enterprise,developer etc.there is no such thing like a developer edition account in a specific edition of salesforce.means you can not create a developer edition in enterprise.
to learn about unmanaged package http://wiki.developerforce.com/page/How_to_Create_and_Register_a_Package
HTH