Michael Phelps took some time to reminisce about his old house and his favorite places to eat. Then the discussion turned to a more serious topic: the 2012 Olympics.

"The light's at the end of the tunnel," said Phelps, of Baltimore. "There are still a lot of things that I want to accomplish, and that's why I'm still here. If I didn't want to accomplish them, I wouldn't have come back. It makes it a lot more fun, being able to have all the memories that you have had at all these places."

Phelps is back in Ann Arbor, the same town he lived and trained in before the 2008 Olympics in Beijing. The 14-time Olympic gold medalist will compete in the Eric Namesnik Michigan Grand Prix, which starts Friday on the campus of the University of Michigan. Phelps is one of several stars on hand for the meet, including Natalie Coughlin, Ryan Lochte and Jason Lezak.

"A lot of the top swimmers have been able to travel to a lot of the Grand Prixs, so the level of racing is a lot higher than normal Grand Prixs I think have been in the past," Phelps said. "It just shows that we're all sort of trying to prepare ourselves as best we can for world championships and try to really get ready and geared up for next year."

After dazzling displays in 2004 and 2008, Phelps has his sights set on 2012. Since he hasn't committed to competing beyond then, there's a sense this could be his final Olympic cycle.

Phelps has a lot to prove in 2011 after his own coach admitted last September that Lochte was the world's best swimmer. Phelps acknowledged that he had a hard time working his way into his training regimen again.

"Trying to get back into the routine … it's just the little challenges, when you don't do them for a while, it's hard to get back on it," Phelps said. "I've been able to make a lot of good improvements."

Last month at the Indianapolis Grand Prix, he looked like the Phelps of old, beating Lochte by more than two seconds in the 200-meter individual medley. Phelps left that meet with five gold medals — one for each event he entered.

He's penciled in to swim seven events in Ann Arbor, although he was coy about his plans Thursday.

"Who knows what will really happen, but that's the rumor," Phelps said. "It should be fun."

Lately, Phelps has been sleeping in what he calls a "tent" in his room that can simulate high altitudes. He says he's been at 4,300 feet, gradually moving up.

"The max is 13,000, but I won't get up that high," he said. "It's different. It literally feels like I'm in a giant fish tank. It's like a giant box around my bed."

The Michigan meet will be another reference point for Phelps as he prepares for the world championships in Shanghai in July — and of course, London a year later.

"There were a lot of times where I just thought maybe it wasn't the right idea, but I know deep down inside that I've never wanted to have that 'what-if' in the back of my head," Phelps said. "Once I retire, I want to be able to say, 'I've done everything I've wanted to do, and I'm happy."'