I haven't ran a dnd game in a few years and a couple of my pc's want to apply some monster templates to their starting characters. Is player level directly proportional to Monster cr? IE: If we want to start the players at lvl 10, and the monster template is cr 5, would the players start at level 5?
A challenge rating is calculated assuming all of the creature's powers are crowded into a single encounter. Player characters get to spread those powers out over the course of an entire campaign... Allowing them to utilize the powers to greater effect.
The number you're looking for is the monster's Level Adjustment. The character's total level ends up as: Level Adjustment + Monster Hit Dice + Levels in a character class.
More information can be found in the SRD: Monsters As Races
No. According to both the DMG(3.5e) and the MM the CR corresponds to a party of equal level. That is to say, a CR-5 creature/encounter should be a moderate challenge for a party of four 5th-level characters. Assuming the characters are fresh going into the battle and come out the other side a bit battered. XP awards are adjusted by the difference between the party's level and the CR of the creature/encounter. (See table 2-6 of the DMG(3.5e). By this table your 10th-level party would receive 500 xp for a CR-5 encounter where the 5th-level party would receive 1,500 XP.)
Things to remember: - Essentially the CR has a direct relationship to the level of the party as a whole, not any individual character. - The CR is based on a four-member party. The CR needs to be adjusted for parties of varied size. - The CR assumes that the party is in top shape and not yet worn down by previous battles.