At Tom Bombadil's House...

[lathspell]

The always returning Tom Bombadil-question [img]smilies/biggrin.gif[/img]

In the case of who he is, i do not know. Some guys thought about Tom Bombadil being Eru, because there a connection. When the hobbits ask Goldberry who TB is, she answers: 'he is'. In the Silmarillion it is said that 'Eru is'.
The only thing that is sure, is that TB ain't Eru: Tolkien said that himself after these guys asked him this. He said that TB is an enigma, but many still have doubt with this. Many people believe he is an earth-spirit and Goldberry a water-spirit. I guess they are Maiar, but not Valar.

As for TB having power over the Ring, I think Gandalf says enough:
1. When Elrond during the Council ponders the question if he should have invited TB, Gandalf answers: 'He would not have come'.

2. Erestor says that TB seems to have power over the Ring. Gandalf answers:

'Say rather that the Ring has no power over him. He is his own master. But he cannot alter the Ring, nor break it's power over others...

3. Erestor at last asks if TB would take the Ring and keep it safe forever. Gandalf answers:

'No,' said Gandalf,'not willingly. He might do so, if all the free folk of the world begged him, but he wouldn't understand the need...'

TB set bounds and beyond that bounds nothing really concerns him. He lives his life in his own 'land', where he is mightiest. Though nothing can harm him there, I think TB can't harm anything else either or undo any evil. And even is he can do it, I think he wouldn't. TB has no concern of what so ever outside his own realm where he is master. That's what I make out of these three quotes.

Inglorion made in a thread on the bd an answer that he's the opposite of Ungoliant: Ungoliant fights both good and evil, he just wants light. TB doesn't fight, except in great need and than only in his own way (like the singing by Old Man Willow).