Citadel Computer Systems Inc, Houston developer of network security and management software, has a letter of intent to acquire fellow Texan Astonishing Developments Inc, creator of the WinShield personal computer security and configuration product line for an undisclosed sum in cash and shares. Citadel aims to ride on the back of Astonishing to migrate its own products into the personal computer market and also integrate WinShield into Citadel’s product line for the network world.