The only thing I'm really doing different is that I don't come up with a list of primary and secondary skills to use. I let the play/description of actions at the table completely determine how skills are relevant. Without a preconceived notion of how the PCs will get to the goal, then it's pretty much a back and forth between the DM and the players.
This is in no way different than what I used to do with other editions, the big difference is that the 4e system gives me a consistent reward system. In previous editions I had to completely ad-hoc that piece and it was not consistent at all. Sometimes they got XP, and many, many, many times they didn't.
Case in point, I'm currently running my home group through a converted A1-A4 (Slavers) adventure. One of the locations in A2 has a Medusa that has been kept in captivity by the Lord Commander of the stockade as a guardian for his treasure. The Medusa hates, and fears the Lord Commander. But when the party shows up, they have already killed the Lord Commander, have told her so, and then showed her the body. The Medusa could have easily started attacking as soon as the party opened the door, but instead this turned into a negotiation for her release. She willingly offered the Lord Commander's treasure, and the PCs offered her freedom.
This was handled as a Skill Challenge. I didn't have this "scripted" as a skill challenge at all. The PCs used appropriate skills for the actions they were describing. In the end they got XP, and the treasure without getting into a combat that would have very probably killed at least one PC. This also allowed me to flesh out this particular monster into an NPC that I'll be using in a subsequent adventure.