When logged in, there is a "watch" tab for each page.
By clicking on that tab, you add the current page and the corresponding talk page (or vice versa) to the collection of pages on your "watch list". When watched pages are changed they will show up on your watchlist.
There is also an option to have watched page updates e-mailed to you, so that the wiki doesn't have to be constantly monitored. To enable watch page email notifications:
- go to 'my preferences' link at the top right of the wiki
- within the email section of the page, select the check box 'E-mail me when a page I'm watching is changed'
- make sure your e-mail address is listed in your profile