magento robots.txt

User-agent: *
Sitemap: http://example.com/sitemap/sitemap.xml

Disallow: /app/
Disallow: /downloader/
Disallow: /errors/
Disallow: /includes/
Disallow: /js/
Disallow: /lib/
Disallow: /media/
Disallow: /pkginfo/
Disallow: /shell/
Disallow: /skin/
Disallow: /var/

Disallow: /api.php
Disallow: /cron.php
Disallow: /cron.sh
Disallow: /get.php
Disallow: /install.php

Disallow: /index.php/
Disallow: /catalog/product_compare/
Disallow: /catalog/category/view/
Disallow: /catalog/product/view/
Disallow: /catalogsearch/
Disallow: /checkout/
Disallow: /control/
Disallow: /contacts/
Disallow: /customer/
Disallow: /customize/
Disallow: /newsletter/
Disallow: /poll/
Disallow: /review/
Disallow: /sendfriend/
Disallow: /tag/
Disallow: /wishlist/
Disallow: /catalog/product/gallery/

Disallow: /*.js$
Disallow: /*.css$
Disallow: /*.php$
Disallow: /*?SID=

Disallow: /*?dir*
Disallow: /*?dir=desc
Disallow: /*?dir=asc
Disallow: /*?limit=all
Disallow: /*?mode*
Disallow: /*?p=*&

http://turnkeye.com/blog/optimize-robots-txt-for-magento/
http://www.byte.nl/blog/magento-robots-txt/
http://www.magentocommerce.com/magento-connect/xml-sitemap-by-activo.html
http://inchoo.net/ecommerce/ultimate-magento-robots-txt-file-examples/