Allen Bradley is the brand name Rockwell Automation uses for it's automation hardware systems, such as PLC's, Motor Controls, etc.
Rockwell Software is the division of Rockwell that supplies their automation software suite. Their main SCADA product is RSView32. This is a mature well developed product that is suitable for most projects. It is a well-thought out package that in comparison to iFix and Wonderware is relatively easy to use.
In the last year Rockwell Software has launched RSView Machine Edition (ME) and RSView Supervisory Edition (SE) as part of their new "ViewAnywhere" strategy.
RSView ME is a cross between their older PanelView and RSView32 products, and is designed as an HMI to single machines or standalone process units. It has a host of excellent features...I am in the middle of developing a medium sized project for a complex multistage vacuum pumping system using RSView ME....and I REALLY like it.
RSView SE is intended as the future flagship Enterprise wide product. It is still a very new product and has yet to develop the capabilities and stability of the more mature RSView32, but within 12 months I expect it to be the leading SCADA product on the market.
The bigger answer to your question is that ALL the major HMI vendors, Intellution, Wonderware, Rockwell Software, Citec, etc can work with almost any PLC. They all have numerous drivers to almost any hardware on any network.
With the advent of OPC 2.0, this task of integrating different PLC's to different SCADA software will conform to a universal standard and it will become much easier to manage multiple data sources and destinations in complex plants.