Google has recently updated their webmaster tools to allow you to see a larger sample of your Google backlinks beyond what the link: operator listed. The data is much more comprehensive and you can sort and even download the information.
The links are currently divided into 2 categories, external and internal links. External links are links on pages other than your site or domain. Internal links are those within your own site or domain.
Google will not reveal all of the external links indexed for your site, but they will reveal a much larger total than the link: operator reveals:
Google knows about more links than the total we show, but the overall fraction of links we show is much, much larger than the link: command currently offers.
For more information you can visit Google’s Webmaster Central Blog and check out Discover your links. Vanessa Fox offers a post about Who links to your site at the official Google blog also.
I’ve a feeling this one will keep webmasters busy for awhile. 😉