load a node content into a lightbox2 (without headers and footer and other blocks)
There are many ways to do this, and this gets asked a lot, please have a look at my answer in this question.

Look at this doc page from the Lightbox2 documentation.

Right now though I highly recommend using the Modal Frame API and Automodal for things like this.

** Drupal 7 update

The colorbox module doesn't offer out of the box support for nodes yet (they are working on a patch for this), but in the meantime you can use this approach. You can also use the Shadowbox module, have a look at this and this issue.