UltraMon will extend the taskbar across multiple monitors. MultiMon offers taskbar support
in Free and Pro versions for XP and Vista and "might" work for Windows 7.
UltraMon – Commercial program
http://www.realtimesoft.com/ultramon/
MultiMon – Free and Pro – this "might" also work for Windows 7 as it does for Vista.
http://www.mediachance.com/free/multimon.htm
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These should help you set up multiple monitors.
How to Setup Dual Monitors in Windows 7
http://www.online-tech-tips.com/windows-7/how-to-setup-dual-monitors-in-windows-7/
Two monitors are better than one
http://www.microsoft.com/athome/organization/twomonitors.aspx
Work and play better with multiple monitors
http://windows.microsoft.com/en-us/windows7/work-and-play-better-with-multiple-monitors
Move windows between multiple monitors
http://windows.microsoft.com/en-US/windows7/Move-windows-between-multiple-monitors
Multiple monitors : frequently asked questions.
http://windows.microsoft.com/en-AU/windows-vista/Multiple-monitors-frequently-asked-questions
Hope this helps.