CLazarus

Beyond what you can get at aviationinterviews.com - Cage interview consulting is a good resource for United in particular, as they are located across the street from United's training center. I used Emerald Interview consulting and felt well prepared. Emerald at least offers free follow on interview prep top off (e.g. already did the full prep for UAL, but now need a top off for an interview at DAL). Aside from interview prep, I assume they also offer application/resume reviews (I didn't use it). The cost of either Cage or Emerald is entirely reasonable and worth it.

Side note - there is already a huge amount of good information on this site. Just search and ye shall find it.