Ignoring a specific portion of the log file (header/footer)

[KidCrippler]

I want splunk to start indexing my log file only after it encountered a specific string/regex.

Everything before that marker should be ignored as I have no use for it.

Is there any way to do that?

Thanks

[ogdin]

For Splunk 6, see:

http://docs.splunk.com/Documentation/Splunk/latest/Data/Extractfieldsfromfileheadersatindextime

Specifically the example on ignoring useless long headers.