The best approach to TL is taking out your controller and battering your opponent senseless with it. On a more serious note (although I do suggest the former), TL is extremely difficult to approach for Ike. His SHDA completely destroys any SHfair approach, bombs to tether can f*ck up our ground game, and boomerang has semi-good priority. CORRECT ME IF I'M WRONG, but I believe Ike's dash attack clangs with TL's arrows, so he can stop you dead in your tracks, but doesn't give you a damage penalty. I suggest you fight TL like you'd fight any good ranged fighter with a tether: air-dodge. Don't approach on the ground, try to keep in the air and wait for opportunities. Wait for a TL to set-up a SHDA or throw his boomerang (pretty decent ending lag) and go for a fair or nair to set-up jabs.
Ike's jab beats TL in terms of fighting face forward, but don't EVER try to approach him when he's looking the opposite direction. TL can easily combo Ike from 0~50% with his uair/bair, but after that he can't really link any moves together.
Here's some videos of Rykoshet's Ike fighting a very good TL:
http://uk.youtube.com/watch?v=65-fORIFeyA - Final Destination, Ike wins
http://uk.youtube.com/watch?v=6r9z-4reY18 - Smashville, Toon Link wins
http://uk.youtube.com/watch?v=i1gYz3qWJyo - Halberd, Toon Link wins (hilarious ending xD)
All videos were from 2~3months ago, but VERY good interpretation of the match-up. HQ videos as well.
I hope that helps!