The sales for two businesses were recorded under one at the start of year. Two separate sets of books are being kept now but there is a $ amount of sales that needs to be removed from on and posted to the other. How do I do this correctly and what are the accounts affected.

Transfer the actual cash and the entry will take care of itself. Say Company A recorded all the sales and needs to transfer to company B. Cut a check for the amount that needs to transfer.

Company A:

Cr Cash xxx
Db Revenue xxx

Company B

Db Cash xxx
Cr Revenue xxx

If this is not possible you will need to set up some kind of intercompany account on both books and substitute it for Cash above. Hope that helps.