For people interested in trading LTC/TRC there is no exchange currently offering this possibility
So trading LTC and TRC IOU's on ripple is the next best thing, I would say

for people interested, but who are not sure how to do this, in ripple:

Trust if you want them to be able to issue IOU's to you
under advanced, trust,  Click  the + and then
for LTC grant a trust to rDihBcUrrfDwUBZWBcuP2z5n47KVLQFNQH this is Chriswen's gateway account, also see https://bitcointalk.org/index.php?topic=155124.0
for TRC grant a trust to rZQGU7Y5ZdLhNWTCV6BKJFcpLijyYVYWX  bitcoinreactor's gateway account http://exchange.bitcoinreactor.com:8032/

Trade order
under advanced, trade, clear the field where you see BTC/XRP or whatever other currencies you see and type TRC/LTC then next to this field you can change the issuer rDihBcUrrfDwUBZWBcuP2z5n47KVLQFNQH for LTC and rZQGU7Y5ZdLhNWTCV6BKJFcpLijyYVYWX for TRC
now you can sell or buy TRC/LTC or see the order book(trusting is not necessary for this). currently only my order 1 LTC for 10 TRC there , I hope to see others soon


Funding
To get IOU's in the first place in your ripple account follow the instructions at https://bitcointalk.org/index.php?topic=155124.0 for LTC
http://exchange.bitcoinreactor.com:8032/ for TRC both issue and redeem their respective IOU's without any added cost during launch phase
alternately you could trade TRC or LTC for XRP or BTC some orders already exist check out the possibilities you can add bitstamp as a gateway for BTC, USD, ...


note: if you just want to trade trusting is not necessary only changing the issuer, trust will be added automatically when you accept an offer

I will do my best to answer your questions