I know I will get the question often in the future, so I'll just summarize some of my thoughts and mainly extracts from other sites here for reference. Makes it easier than explaining it all over again and again :-)
Countless cultures point to the raven as a harbinger of powerful secrets. Moreover, the raven is a messenger too, so its business is in both keeping and communicating deep mysteries.
It is a bird closely connected with battle and the Celtic goddess Morrigan, who was a remarkable prophetess (connecting oracle themes with the raven).
Raven symbolism of wisdom and knowledge-keeping is connected with the Welsh hero Bran, the Blessed whose name means raven. Bran was the holder of ancestral memories, and his wisdom was legendary.
Odin was also known as the Raven God. He had many daughters known as Valkyries who could transform into ravens.
There is much more to this enigmatic and intelligent bird than death, darkness and destruction. Raven is a trickster, a protector, a teacher. and a bringer of great magic.
The symbolic meaning of the Raven in Native American Indian lore describes the raven as a creature of metamorphosis, and symbolizes change/transformation.
In some tribes, the Raven is considered a trickster because of its transforming/changing attributes.
Often honored among medicine & holy men of tribes for its shape-shifting qualities, the Raven was called upon in ritual so that visions could be clarified. Native holy men understood that what the physical eye sees, is not necessarily the truth, and he would call upon the Raven for clarity in these matters.
Foremost, the Raven is the Native American bearer of magic, and a harbinger of messages from the cosmos. Messages that are beyond space and time are nestled in the midnight wings of the Raven and come to only those within the tribe who are worthy of the knowledge.
The Raven is also called upon in Native ritual for healing purposes. Specifically, the Raven is thought to provide long-distance healing.
The Raven is also a keeper of secrets, and can assist us in determining answers to our own “hidden” thoughts. Areas in our lives that we are unwilling to face, or secrets we keep that harm us – the Raven can help us expose the truth behind these (often distorted) secrets and wing us back to health and harmony.
More info: http://en.wikipedia.org/wiki/Cultural_depictions_of_ravens
The anvil stands in connection with the old-northern divinities of the smith's art. New life forge, beginnings create, new get going is the spiritual message which he transports. Anvil is a symbol of the virtue, bravery and strength.
A symbol of the earth and of matter. It corresponds to the passive and feminine principle, as opposed to the hammer, which denotes fecundation.
The anvil is a symbol of universe being forged and can also represent martydom.
More info: http://en.wikipedia.org/wiki/Anvil
Those are common interpretation of both symbols. Finally, I'd like to add a definition of the combination as per http://www.thefreedictionary.com/To+be+on+the+anvil:
"To be on the anvil": to be in a state of discussion, formation, or preparation, as when a scheme or measure is forming, but not matured.
So, these are common meaning. What do they mean to me? That you'll have ask me next time we meet each other if you're interested :-)
References: search google for raven symbolism and anvil symbolism.