Currently there are a few +spell damage craftables in the tailor profession in Burning Crusade. This is just a short write-up of what is currently known about these.

Chest: Netherweave Tunic, green. +46 damage, +45 STAM.

Legs: Imbued Netherweave, blue. +30 damage, +10 MP/5, +39 STAM, +26 INT.

Waist: Girdle of Ruination, purple. +30 damage, +26 spellcrit, red and yellow socket, +4 STAM socket bonus.
or
Waist: Netherweave belt, green. +26 damage, +30 STAM.

Back: Cloak of the Black Void, blue. +35 damage, +11 INT.

Wrist: Bracers of Havok, blue. +30 damage, +12 INT, yellow socket, +2 spell crit socket bonus.

Feet: Imbued Netherweave Boots, blue. +23 damage, +30 STAM, +21 INT, +8 MP/5

Hands: Netherweave Gloves, green. +28 damage, +30 STAM.

In addition, tailors can now make armor-kit type enchants for items, that either add +27 dam or +51 heal and +18 STAM. These items are epic and need quite a few ingredients.

So, in total a tailor can equip himself in a mix of greens/blues and maybe an epic or 2 and receive:

+310 spell damage
+28 spell crit rating
+70 INT
+144 STAM
+3 sockets
+18 MP/5

The green Netherweave contains only +stam and +dam, so it's better for locks than for the other caster classes. Netherweave is a 8 piece set with 2 chest pieces, os it's actually only 7 pieces.
Imbued Netherweave is a 4 piece set-up and is more or less and upgrade of Netherweave, since it contains a bit less stam and dam, but has int. As such it's a much better optoin for non-locks.

Leaving head, shoulder, trinket, jewelry and weapon slots open for more +damage. Also include gems and chants and you are looking at an easy +500-600 spell damage if you fill out the rest of your slots with damage gear.

Now, a lot of these items will be easily replaceable by loots from bosses in the new instances, so I personally wouldn't level tailoring to gear myself. But htat's hte case of all professions in WOW. You are much better off leaving the hard work to others and just buy what you need from crafters.

I am also working on a guide to +dam gear drops, so stay tuned for that :)