here's a grep for "sitemap" in my server logs.
Pretty clear,
66.249.76.156 - - [18/Feb/2013:02:53:51 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 471 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:02:53:52 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:02:53:52 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:02:53:53 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:03:04:23 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 469 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:03:04:24 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:03:04:24 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:03:04:24 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:07:50:00 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 469 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:07:50:00 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:07:50:01 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:07:50:01 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:08:04:15 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 471 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:08:04:16 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:08:04:17 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:08:04:17 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:09:01:00 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 469 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:09:01:00 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:09:01:01 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"
66.249.76.156 - - [18/Feb/2013:09:01:01 +0100] "GET /sitemap/sitemap.xml.gz HTTP/1.1" 200 468 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
http://www.google.com/bot.html)"