[Tirned Tinnu]

Why did Frodo go?
I don't think Frodo really wanted to go. In the beginning, he was acting for the preservation of the Shire. Once in Rivendell, he was warned that Elrond would not suffer the Ring to stay there.
Finally, when the group at the table began to debate who should carry the Ring it became clear to Frodo that there was no-one else who had experience with it, no-one else really to trust. Bilbo was worn out, and it was his family's "fate" to make sure the Ring found itself to its finally resting place...

Also, I think what you read coming out of Frodo's mouth is directly related to the power of Gandalf, his ring, and his teachings.
Nowhere else were there beings so motivated as those in the presence of the wizard - they seemed to have the might of old, a stirring of the heart to do great deeds. I think that this coupled with Frodo's interest in travel that made up Frodo's mind in the end. It also could be argued that Frodo was "channeling" the will of the Valar, but we have no solid evidence of that, just mere comments that seem to pop out of no-where.
The saddest part of this is that Frodo really had no idea how much hardship he was in for.
Perhaps only Aragorn, Elrond, and Gandalf understood the weight of his decision. As the party leaves Rivendell, it seems that the only person who shows any remorse or worry is Aragorn, who huddles on the steps with his head tucked against his knees, in a ball.
It's my opinion that he felt not only for himself, but for Frodo and the other little Hobbits that he was about to see into mortal danger. Frodo was just beginning to understand by then...

[ October 05, 2002: Message edited by: Tirned Tinnu ]