RoboM:
I have an Arduino Duemilanove board and as its mentioned in its website that the Input Voltage (recommended) is 7-12V and Input Voltage (limits) is 6-20V. I would be grateful if somebody could inform me about that is the maximum current can Arduino board operates without any issue from a rechargeable battery?
Volts measure voltage not current. Current is measured in Amperes, and is something that is drawn by the load, not pushed by the battery.
If your rechargable batter provides any voltage between 7V and 12V, it will be great for powering the Duemilanove through the DC-in jack. If it provides any voltage between 12V and 20V, it will still work, it just won't be the best source for the job. Trying to go below 7V may result in flaky behavior -- some people say 6V works fine, others find it doesn't.