Hehe, so for those of you who have already read wilkipedias details on X2, X-Men United then you'll probably already know these, if not I'm so lame I actually thought you might like to know these things lol.
Bryan Singer (director) and several crew members are shwn to be the guards who keep a check on Magneto.
Bryan Singer wheels Professor Xavier into Magneto's plastic prison.
Just a few names on the computer screen that Mystique looks at. All of them are Marvel characters however not all of them made it into the movies. Samuel Guthrie (Cannonball) Paige Guthrie (Husk) Keniucho Harada (Silver Samurai) Garrison Kane Remy LeBeau (Gambit) Eric M. Lensherr (Magneto) Elisabeth Braddock (Psylocke, who appears briefly in X-Men: the Last Stand) Lorna Dane (Polaris) Roberto DaCosta (Sunspot) Angelo Espinosa (Skin) Sean Cassidy (Banshee Theresa Rourke Cassidy (Siryn, the latter of whom is briefly in X2 and X-Men: The Last Stand) Allison Blaire (Dazzler) Bobby Drake (Iceman) John Allerdyce (Pyro) Artie Maddicks Jamie Madrox (Multiple Man, who appears in X-Men: The Last Stand) Xi'an Coy Mahn (Karma) Pietro Maximoff (Quicksilver Wanda Maximoff (Scarlet Witch, though their first names aren't seen) Kevin McTaggart (Proteus, though his last name is misspelled) Tom DeSanto (Executive Producer of the film) Danielle Moonstar (Psyche / Mirage) Ororo Munroe (Storm)
Here Magneto is seen reading The Once And Future King by T.H.White. At the end of the film when just before Jean's little speech, Xavier asks the students if they've ever read a book by a famous English writer known as T.H.White called The Once And Future King
In the bar scene where Mystique pretends to be a hooker this is shown on the T.V in the background. Unfortunatley it's not Kelsey Grammer who plays him in the third film. As well as this you can see that here he is still human and not happily transformed into his beastil state like in The Last Stand. In this shot he is debating about mutants with the black king Sebastian Shaw.
Finaly a shot i nticed myself in which you can see the names of a few other mutants from the comics. If you look hard enough lol. The names I've managed to spot are: John Allerdyce Everett Thomas Cecillia Reyes (sp) Viktor Creed Nicholas St Cruise Kurt Wagner Raven Darkholme Jamie Madrox Wade Wilson (sp) Scott Summers Alison Blaire Remy LeBeau Bobby Drake Paige Guthrie Yuriko Oyama Tom Cassidy Artie Maddicks Eric M Lensherr Calvin Rankin Dr Nathaniel Essex Garrison Kane Illyana Rasputin Theresa Rourke Shiro Yoshida Ororo Munroe Katherine Pryde Omega Red Xavier's School Blackbird Massachusetts Academy Trask Zero Turbulance Project Wide Awake Beta Flight Jamie Braddock Cerebro Danger Room Forge Dept H Brotherhood Weapon X Gamma Flight Rahne Sinclair Legacy Franklin Richards Alpha Flight Muir Island Morlocks Kevin McTaggert