Since nobody can really answer the questions you asked here, I recommend Trillian for all in one messaging on multiple accounts. As for Twitter and Facebook, Seesmic works great, with multiple accounts as well. Hope that helps.
Not sure what ^^ up there is flappin about but there are some goo recommendations here.
Trillian was the free app on amazon a couple weeks back, I picked it up as one of those you never know apps. It was free and you never know when it can be handy. It works for almost all chat programs including facebook chat. The only downfall I see is it doesnt support skype chat but /shrug.
As for twitter I use plume (formerly Tourtier) paid version. Other people use the stock installed one twydrod (i think), seesmic, and tweetdeck. Truly for those apps it is best to test them out and see if they will work for you. I use the android fb app for that so I cant comment on how the other apps integrate with it. However I did use seesmic for pc and sorta liked it.
I'm also looking for a cross platform messenger, what did you think of trillian?
Also do any of these messengers work with sms? I have Ultimate Juice set up to turn of data and wireless when he screen is off so a messenger that uses data wont work with my current set up.
meebo, ebuddy or trillian for messengers. Prefer meebo or ebuddy since it's free. I use trillian though, just too used to it, used it on pc and just kept it when switchin
eBuddy has this annoying problem where when you stop typing it sends the "has stopped typing" hint to the person you're chatting with incessantly.
I have argued with the author of the app, who mis-understands the intent of the "has stopped typing" hint.
The intent of it is to inform someone when you have paused your typing temporarily while typing a message (and not when you have stopped typing because you're done), but he believes the hint should be sent any time the user stops typing, even if they have just sent a message.
The result is that when the other person closes your chat window it will pop back up and tell them that you have stopped typing.