Simplest for me is to use a ProgressIndicator in the interactive notebook: ProgressIndicator[Dynamic[VariableForMapCurrentPosition], {1, LastMapIndex}]

Then have your Map function update 'VariableForMapCurrentPosition' . Two other comments:

1. As @Szabolcs wrote above, there is more information in previous similar questions.
2. This doesn't work well with Parallel. You can simply SetShared your position variable, but at least in my case it slows things down -- more than double the time. This post has more on the topic: Monitor doesn't work with ParallelTable

Simplest for me is to use a ProgressIndicator in the interactive notebook: ProgressIndicator[Dynamic[VariableForMapCurrentPosition], {1, LastMapIndex}]

Then have your Map function update 'VariableForMapCurrentPosition' . Two other comments:

1. As @Szabolcs wrote above, there is more information in previous similar questions.
2. This doesn't work well with Parallel. You can simply SetShared your position variable, but at least in my case it slows things down -- more than double the time. This post has more on the topic: Monitor doesn't work with ParallelTable