Clawlock isn't from dragon magazine
It's a name for the warlock that specialises in natural claw attacks
Clawlock: The clawlock uses the Eldritch Claw feat from Dragon Magazine. More than any other warlock build, the clawlock is a damage dealer. Their damage potential is very good, since they can stack anything that helps natural weapons, unarmed strikes, manufactured weapons and eldritch blast. Clawlocks depend on Dragon Magazine material, which is frowned upon on some tables, so ask your DM before building one.
Feats for the Warlock
Able Learner (Races of Destiny): Human only. Your class skills remain with you forever. Good if you're dipping or if you want to qualify for Chameleon.
Eldritch Claws (Dragon 358): As a free action, create a pair of claws. Damage is based on unarmed strike + eldritch blast. This is crazy good - you get to stack bonuses from plenty of sources, it has synergy
with lots of things, the damage is really good.
Beast Strike: Adds your claw damage to your unarmed strike damage. Very good feat for clawlocks.
Improved Unarmed Strike (PHB): By itself, not that good of a feat. It's useful as a requirement, though.
Grappling Blast (Dragon 358): Allows you to grapple and deal eldritch blast damage, giving a bonus in the next grapple checks. I can see this being useful in a grappler build that dips Warlock, but increasing actual size is not that good for warlocks. I'd skip it.
Superior Unarmed Strike (Tome of Battle): Clawlocks should either take this or enter Shou Disciple. Solid damage buff.
Improved Natural Attack (Monster Manual): Clawlocks can take this feat, but they can also get it from Thayan Gladiator or the Fanged Ring. You could take this for unarmed strike as well, but you can (and should) use (Greater) Mighty Wallop instead.
Planar Affinity (online): Change two invocations instead of one. Quite lackluster. Useful in a few tricky situations (see Enlightened Spirit).
Infernal Adept (online): Opens up the Dragonfire Adept invocation list for you. Could be quite strong - we'll mention your options later.
Weapon Finesse (PHB): Glaivelocks should probably take this. You can use Str to attack with eldritch glaive, but that's all you'll ever get from it. Dexterity, on the other hand, applies to plenty of other stuff - initiative, Dex, Balance, Tumble, ranged attack rolls, Reflex saves... You can even be a finesse clawlock, though of course your damage output will suffer. However, if you're a ranged warlock that just uses glaive/claw onde in a while, I'd skip it.
Touch/Ray Spell Specialization (Complete Arcane): Low, low damage bonus. Not a requirement for anything. I'd skip it.
Obtain Familiar (Complete Arcane): Familiar are pretty useful, since they represent a second set of actions.
Improved Familiar (PHB): Now we're talking. Some improved familiar can speak and use magical items, so you could give them wands of important spells that can be cast during combat to save you actions (Nerveskitter and Snake's Swiftness spring to mind). If you're a Hellfire Warlock, give your familiar a Rod of Bodily Restoration and don't worry much about complaints of cheese.
Point Blank Shot (PHB): Low bonuses, only good as a requirement for Psionic Shot.
Precise Shot (PHB): Don't take this. Touch attacks are reliable enough and you need your feat slots for better stuff.
Mortalbane (Book of Vile Darkness, page 49): No alignment requirements, despite coming from BoVD. 5/day, get +2d6 damage on a damaging spell-like ability. This is a very good damage boost for eldritch blast and the lack of requirements make this a very good choice for your 1st level feat. Fades in usefulness as you level up, but it's still handy.
Empower/Maximize/Quicken Spell-like Ability: These feats are all very good for a warlock, since spell-like abilities are our bread and butter. Since eldritch blast counts as a 1st level spell (see the errata for Complete Arcane), it's a prime candidate for these. Empower SLA is not exactly worth it - the bonus is pretty low. Quicken & Maximize are very good options. Notice you can take those feats for other invocations, but unless you're spamming them I would advise against it.
Practiced Spellcaster (Complete Arcane): At first glance, this is a piece of crap. It helps you defeat SR and dispel... and that's that. However, Richard Baker himself said he would allow it to advance the Warlock's eldritch blast. If your DM accepts this ruling, this is very good news for any Warlock that dips around.
Supernatural Transformation (Savage Species): This feat does not work with invocations, sadly.
Surrogate Spellcasting (Savage Species): Requires Wis 13, but warlocks don't depend on ability scores as much as other classes. Allows your hengeyokai/tibbit warlock to use invocations in any form. Now you really can be a sparrow of death!
Mindsight (Lords of Madness page 126): This feat is so good that if you qualify for it you should take it. Blindsense plus detecting Intelligence and creature type?! If you dipped Mindbender of if you are a Shimonen Naga, you shouldn't ask yourself "Should I take this feat?", you should ask yourself "When should I take this feat?" with the anser being as soon as possible.
Extra Invocation (Complete Arcane): You need more invocations, but this feat by itself is not the most optimal way to get them. If you have access to Psychic Reformation and/or Embrace/Shun the Dark Chaos it becomes better... but if you want versatility that much you really should be dipping Chameleon. All things considered, a necessary evil for many builds and a good filler feat if you don't know what else to take.