I`m currently doing some research in connection with Bomber Command and have identified some excellent resources in addition to those already identified by the respondents to this thread.
One thing I have learned though is that some of the most unlikely looking Websites have some truly remarkable personal accounts of individual operations, aircraft and their crews.
As already mentioned though you'll need to provide a bit more information about the aircraft in question. If you provide that information I`ll certainly keep a look out for references.