Please check out [url=http://www.phy.ntnu.edu.tw/demolab/CoLoS/JaCob/]JaCoB[/url].
Click [b]Electricity[/b] at the right frame, then click [b]Two cylinders[/b].
May be it is what you want. There are a lots of possibility with JaCoB.
The following is a demo. You can also check out [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=319.0]Image charge: point cgarge and a sphere[/url]

[flash=708,592]http://www.phy.ntnu.edu.tw/ntnujava/swf/jacob.swf[/flash]

The following is a JaCoB applet.?Move your mouse inside  and [b]right click[/b] for menu to generate objects, charges ...etc.
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Check out attached image!

Download jacob.zip and open Jacob.htm with your browser.