As someone who spent some time today trying to find out how to change the user in Eclipse, let me save you some time if you meet this issue…
There is a Mercurial menu in Eclipse with a username and there is also the hgrc file in the .hg Mercurial repository. Changes these will not allow you to switch the user in eclipse.
What you need to do is to choose the synchronise with option in Eclipse (rather than Syncronize). Up pops a dialogue box with the user and password used by Eclipse. Change these and you are in business…
