How do i remotely create a publish to some user's blog after he/she provides me with his login info while using wordpress api? What method should i use, what paremeters should it have, etc? Sample code is going to be great.

I'd would rather make use of the XML-RPC api but others may also be acceptable.

yeah you should use metaWeblog.newPost or blogger.newPost, a good example of the very first:

uses curl and xmlrpc_scribe_request

a good example of the 2nd:

yeah and @Francis is correct