For tree testing and card sorting I agree with ASHM, the Optimal Workshop suite seems to be the best.
I was having a look at the list of tools for Evaluating Information Architecture and I was wondering about some of the tools mentioned there.
Maybe somebody in the community can help
BagelHint: is this service active? has anybody used it recently?
Boardthing: same doubt...
ConceptCodify: it doesn't exist anymore
Naview: the website has not been updated in a long time, I suppose this tool is not available anymore...
Plainframe: it doesn't exist anymore
SimpleCardSort: is this service active? has anybody used it recently?
Websort: it doesn't exist anymore