Rossie Cast

Jason Behr is Max - Max Evans is sort of the unofficial leader of the pod squad.  He is very trustworthy and nobel, is always very cautious and very rarely uses his powers.  Max and Liz have known each other since third grade but have never really been anything more than casual friends.  In the pilot episode, when Liz is accidently shot, Max realises that he has loved her his whole life but has been in denial the whole time, him being an alien and all.  In a moment of madness, Max puts his hand over Liz's wound and miraculously heals her!  Thus revealing his alien-ness to her.
Later on in the episode, when Liz asks him why he saved her, his reply is simply "because it was you".  At this stage you feel it's just a question of 'will Liz fall for the alien boy with the greasy hair?'  But no, for when Liz finally does fall for him he has a sudden change of heart and says that they can 'just be frinds'  (Heartbreaker plays in the background)!
Incidently, you may recognise Jason from a few episodes of Dawson's Creek.  He played Chris.  You know, the one who went out with Abby (the bitchwoman) and once invited all the gang round to his house to study.

Shiri Appleby is Liz - Elizabeth Parker was once a girl who had it all.  She was young, beautiful, had shiny hair and was a straight A student.  Okay, she is still young and beautiful, still has shiny hair and is still a straight A student.  The point I was trying to stress was that since she found out about Max, Michael and Isabel her whole world has been turned upide down.  You see, she used to live in this small and simple life where the only thing she really needed to worry about was getting good grades and making sure her ridiculously shiny hair is never out of place.  And, though both of those things are important, she now has a secret so important that it's got he FBI special unit out looking for her, hoping to get some info on Max and co.
At the start of the series she is, in my opinion, one of the best characters ever to come out of the WB.  She loses a lot of her backbone towards the end of the series, though, and becomes a sort of Max shrine.  And trust me, you will get tired of hearing her say "thank you" in that all-American accent of her's.  And that Journal!!!!  Would somebody please just burn that bloody thing right now!
Other than that she's pretty cool.

Brendan Fehr is Michael - Michael.  Michael, Michael, Michael.  Nope, I can't take it.  There are just too many jokes!  The hair!  The frigging hair!!!  What was Brendan thinking?!
Okay, I'm calm.  Sorry if that disturbed anyone.  It's just, the hair!  Actually in series 2 he is going to wear it down, which is (believe it or not) even more disturbing!
Michael Guerin is not one to let out his emotions.  He (unlike Max and Isabel) was not found by the Evans' by the side of the road and has been moving from foster home to foster home all his life.  As a result of this the only people he really trusts are Max and Isabel and he refuses to get close to anyone else.  Of course, you can rely on Maria to burst that little bubble though it does take one hell of a long time for her to achieve it.
Michael is also the best form of advertisment the 'Tobasco sauce' makers have ever had.

Katherine Heigl is Isabel - Sexy, sassy and extremely...err, what other adjective begins with s?  Isabel Evans is a blonde with an attitude.  She is one of the most popular girls in school and can be very self-centered.  However, underneath that 'I'll-take-no-shit-so-don't-offer-me-any' attitude lies a kind and sensitive girl who is just terrified of being found out.  When she was little she used to have nightmares about Sherif Valenti where he was a wolf and was out looking for her, getting slowly closer.
Isabel was terrified when she found out that Max had saved Liz.  She would not believe that she could trust any human and, like Michael, was very hostile to Liz and Maria for the first half of the series.
I think Katherine Heigl is one of the best cast members on the show.  She could have a very bright future ahead of her.

Majandra Delfino is Maria - Maria De Luca is basically Liz's wacky sidekick.  That's just about all there is to say.  She is easily the most amusing character of the group.
Maria and Liz have been friends since just about ever and trust each other totally.  She is probably the most realistic character as well in the sense that, unlike Liz, her reaction to finding out about Max + Co was not to say "Oh really, you're an alien, I didn't know that"  but to say something like "You're an Alien!  EEK!  Aliens!  They'll eat us all!"  In the third episode she came very close to telling Valenti but changed her mind in the last minute.
One of the best things about Maria is that, if you don't like her hair one week, she'll probably have changed it by the next week.

Colin Hanks is Alex - Okay, before I start the answer to your question is yes, Colin Hanks is the son of Tom Hanks.  However, dispite the reputation of his dad, poor old Colin can hardly get himself any screen time.  In fact, at the start of the series he was lucky to get more than one scene per episode.  That changes later on in the series and he will probably end up being one of your favorite characters.  He is funny and....yeah, the word is definately perky.  Alex has been Liz and Maria's best boy-buddy since fifth grade but they start to drift apart as Liz is forced to continue lying to him throughout the series.