Gives your Chill effects a chance to grant you the Fingers of Frost effect, which treats your next spells cast as if the target were Frozen. Lasts 15 sec.
Your next 2 Frost spells treat the target as if it were Frozen.
Duration: 15 seconds
Gives your Chill effects a chance to grant you the Fingers of Frost effect, which treats your next spells cast as if the target were Frozen. Lasts 15 sec.
Fingers of Frost is a Mage talent in the Frost tree. It causes spells with chill effects such as Frostbolt and Cone of Cold to occasionally grant the Mage a buff that makes their two next spells treat the target as if it were Frozen, but not really freezing it.
For example, if the mage has the buff and casts an Ice Lance, it receives the Frozen bonus and does triple its normal damage.
Being a self-buff and not an actual freeze, this effect works on enemies that are otherwise immune to freezing effects (for instance, raid bosses). This means little in the way of Shatter Combos, though, as the two spells you want to use on the charges are always the higher damage Frostbolts instead of Ice Lances.
This talent shines when used in conjunction with Shatter, causing the spells to be cast under its influence to have a high chance to critically strike. Taking it improves a Frost Mage's mobility by making him able to cast high-damage Ice Lances on the run.
This talent shares a proc roll with Frostbite, so both talents will always proc at the same time when maxed out. This, while redundant, does still give you the opportunity to root your opponent, run away and cast the Lance within 15 seconds if it seems better to do so, instead of having to break Frostbite.
A mage can use a "third" charge due to network latency. This is faciliated by using a spell with a cast time greater than then GCD to consume the second charge, and then using an instant cast spell (Deep Freeze or Ice Lance are the best options for this) right as the spell finishes casting.
In PvE environments, making use of this third charge is not recommended because the poor Ice Lancecoefficient makes it receive little spell power when compared with Frostbolt due to its instant cast time, making it lag behind in terms of damage with a very modest amount of +spell power gear. This discrepancy is such that casting 60% of a Frostbolt in the Shatter Ice Lance's 1.5 GCD time is better in terms of DPS at average Naxxramas gear level (~1500 spell power).
In PvP, channeling two Frostbolts and then immedeately following with a Deep Freeze can be a devestating combo, since the Deep Freeze allows another two-three spells (depending on spell haste) to hit the already weakened target.
This couples perfectly with Improved Blizzard, since the snare component is refreshed every time that Blizzard ticks.
Edit
Patch 4.0.3a (2010-11-23): Fingers of Frost proc chance is now 7/14/20%, down from 10/20/30%. 
Patch 3.3.0 (2009-12-08): This talent now triggers immediately on casting a spell rather than being delayed until the spell strikes the target. 
