Mail problems? cannot send mail


hello and a thouroughly goo evening to one and all who have kindly clicked their way to me and my lowly question. I feel a bit of a dunce as this is now a problem that i has haunted me for a while but somehow in the past i have managed to spoon my way through and get it working somehow.
I have just upgraded to the Tiger and am loving it it. Mail is snazzy looking and seems to be fetching my mail from my POP3 yahoo account without any problems, however, when i try to send any emails i am given a message saying that it cannot get through to the server. I am online in all other respects and able to retrieve mail as i said. I have had a fiddle with the advanced settings and thought that maybe during installation of mail i had not selected to use authentication when getting mail, i have tried to no avail to change settings somehow, but feel like i am getting nowhere fast.
when i now try to send mail i get
Please enter the password for user “apresubu” on SMTP server “”
this is strange as i have entered and saved my password in the advanced settings?
can any one shed any light on this problem, i have been offered a great job and desperately need to send some of my art work by the morning.

your time and help are greatly appreciated.

this is one very tired ginger squirrel over and out
That should be correct sending procedure, but how ever until you solve this can i suggest to send your files immediately by logging onto and use their web base email so you don't miss out on your job

cheers :)