ExportCrawlLog is an STSADM command extension that provides the ability to export Crawl Log messages and gather summary information about crawls based on the information in the crawl log.
The ExportCrawlLog tool must be run a server that has the Index role on it, and must be run with an account that has permissions to the SSP dbs.
The ExportCrawlLog supplies the following capabilities:
stsadm -o ExportCrawlLog
-t (d|s|c|p) -site <portal url> [-outfile filename] [-history] [-s startdatetime] [-e enddatetime] [-from #] [-thru #] [-cat (Portal_Content|ProfileImport)] [-csid #] [-msgid #] [-u url pattern] [-hostname hostname] [-mt (s|w|e)]
where -t = type: d=details, s=summary, c=content sources and start addresses
where -mt = Message type to include in output (applies to -t d only, if -mt is used only one message type can be specified, when -mt is omitted all types are emitted): s=success, w=warnings, e=errors
where -csid = the # of the content source, which you can spy in the query string of the url of the Content Source edit page.
stsadm -o ExportCrawlLog -t d -site "http://moss.litwareinc.com" -history -outfile output.log -s "2007-10-30T15:10:26-05:00" -e "2007-11-01 11:00" -mt e
stsadm -o ExportCrawlLog -t s -site "http://moss.litwareinc.com"
stsadm -o ExportCrawlLog -t c -site "http://moss.litwareinc.com"
Here's a nice summary: http://blogs.technet.com/paulki/archive/2009/02/04/using-the-exportcrawllog-stsadm-extension.aspx