Can Bitcoin be used in QuickBooks? I'm wondering if I can manage my bitcoins with my other securities? Or incorporate them into a business plan.
Sure you could However it would be necessary to know how you transact with the coins...do you simply trade them out for fiat immediately?  If so, then I would create the payment as a check from the exchange for the dollar equivalent that was collected and put the transaction ID and recipient address in QB.  You should probably setup something like coinpunk or at least a full wallet server so that you can issue one time use addresses that are meant to be tied to your customer's account.  This way, it will be easier to reconcile later.  If you try to process your payments together manually into your own wallet, then I at least suggest to create a new wallet each month so that your transactions can be bundled together for ease of reconciliation purposes.

I don't think that you can add XBT as a currency yet within QB but then again I haven't used it in a couple years now.