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Two news sources discuss budget requests by the Secret Service for upgrades to their IT systems:
http://abcnews.go.com/Blotter/story?id=7644369&page=1
http://www.wired.com/threatlevel/2009/05/secretservice/
Although both articles refer to problems with the USSS "communications" systems, a deeper read seems to indicate the problems exist with computer networks and information security.
In addition, there is congressional testimony that you can read here:
http://appropriations.house.gov/Witness_testimony/HS/Mark_Sullivan_03_25_09.pdf
There is some reference to incompatible "telecommunications" between the US Secret Service and the White House Communications Agency (WHCA), but again, I think it refers more towards computer network and phone communications.