Player Character Conversion
There are numerous occasions when you might want to bring a d20 character into the Storyteller system. The most obvious is if you had a character in a d20 Modern game who you'd really like to play in the World of Darkness. Alternatively you might have been playing a character in a historical D&D campaign and decided you wanted him in, for example, Mage: Sorcerers Crusade. For the more thoughtful/humourous campaigns there is always the possibility of Planeshifting...
Storyteller is used for a very wide range of games so I'm not going to go into the mechanics of converting magic systems, psionics or anything campaign specific (after all would a D&D Wizard be a Hedge Magician or an Awakened mage? Answer- largely depends what sourcebooks you've got and whether your Storyteller prefers Mage or Vampire). If you want to add note on such subjects you are more than welcome.
Core Stat Equivilents
Storyteller/d20
Physical
Strength=Strength
Dexterity=Dexterity
Stamina=Constitution
Social
Charisma=Charisma
Manipulation=Average of Int and Cha
Appearance=Charisma
Mental
Perception=Intelligence
Intelligence=Intelligence
Wits=Wisdom
Core Stat Conversion
If you have d20 scores over 18 I would advise making sure your Storyteller knows before springing your PC on him
d20->Storyteller
As a rule of thumb just get your d20 PC's stat modifier and add 1 (minimum=1). If you end up with a result over 5 you had an insanely powerful d20 PC! Check with your storyteller.
Knowledges, Talents, Skills, Merits and Feats
Most d20 Skills should convert accross nicely. A +1 bonus from a d20 Skill = 1 level in the equivilent Storyteller Skill, Knowledge or Talent; with a cap of 5. If you have an abnormaly high level in a skill (eg Tumbling Rank 15), check with the Storyteller: you are not getting a skill over 5 hovever such extremely high abilities may qualify for some form of Merit; but remember the Storyteller's word is law. Most d20 Skills have a Storyteller equivilent, if they don't there seems little harm in including them as additional 'new' skills.
Feats present a more complicated picture. Combat Feats translate to Storytelller abilities such as Melee. Assume that any basic proficieny Feats give you 1 point of the relevent storyteller ability (eg Martial Weapon Proficiency grants you Melee 1) each two additional bonuses count as an extra level. If this brings you above 3 in a combat ability you'll have to have mediation from the Storyteller. You can't get higher than 5.
Special Feats translate as Merits and due to their nature must be taken on a case by case basis with the Storyteller having the final say on any conflict (it is her/his game). Generally a simple feat granting you, for example, a +1 or +2 in a check can translate as a Merit granting +1 or +2 dice in the equivilant roll and situation. Modifiers over +3 require consideration and adjustment. Storytellers may in certain cases prefer to replace some modifiers with adjustments to target difficulty numbers
Equipment
For equipment simply look up the equivilent. If your d20 character has a short sword that does 1d6 hp damage, then look up a short sword in a Storyteller book to discover that it now does Str+2 dice of damage. If there is no entry for your Nitashiwa Ninja Deathbringer then look up something that does a similar amount of damage. If you are still stuck, you'll just have to get the Storyteller to make a final ruling
The obigatory Rope, hemp (50ft) translates to Rope, hemp (50ft)