I found a useful article that gives you a detailed instruction on how to synchronize your bookmarks between different computers using Firefox. Unfortunately its only working for Firefox but its better than having no option at all. You only need a Firefox extension and a way to save your bookmarks on a server. The article helps you in finding a server on which you can save your bookmarks. Its not necessarily if you have a network connection with the other PC or an usb stick.

Update: The guide is no longer available. Recent changes introduced in browsers such as Google Chrome, Firefox or Opera allow users to synchronize their bookmarks and other data automatically between devices. These methods usually work only between browsers of the same type so.

Firefox users can for instance make use of the built-in Firefox Sync feature that they can use to synchronize bookmarks, passwords and other user data. Opera users have Opera Link to do the same, and Google Chrome has a similar feature that you can access under Wrench > Options > Personal Stuff. When you sign in with your Google account, your personal data gets saved to the cloud and synced with all versions of the browser where you are signed in as well.

A user account needs to be created before bookmarks and other data can be synchronized though.

There is also Linkman Lite which allows you to synchronize bookmarks, and an article where I look to find the best bookmark manager.