I am thinking very hard about doing this in August '08 with a friend of mine but, should I be concerned about safety?

What groups or companies offer affordable, dependable and safe trips?

What kind of safety are you concerned about? Inca Trail, and other trails (Salkantay, Lares) to Machu Picchu, are safe to do, for people of all ages. It's nothing really challenging, unless you're heavily overweight, or out of shape.

I did this trail a few weeks ago with Andean Life.

Physical challenge: The hike was kind of challenging (for some parts) but well worth the effort. The company was extremely well-organized and real nice food as well. Although I did do a fair amount of day-hiking in New England, the weight of the backpack and the altitude have 'some' effect. I also pulled it off after a day hike down Colca Canyon 2 days prior.
If interested, you might wanna work on the walking-with-backpack part if you don't intend to hire a personal porter (not required, in my opinion). I did also see extremely well in shape and those not so much on the trail.

Personal safety: Given the time that you are going, you'll have no problem running into other people and will find it hard not to see other hikers.

If you need more info, feel free to PM.

I'm doing the 4 day hike this coming Jan.2008 and using Peru Treks. They have great reviews and seem to be a well known tour group and a little bit cheaper than some of the others.

Safety on the Inca trail should be the last of your concerns - it's perfectly safe.

My advice would be to book well in advance - the Inca trail gets booked up months in advance.

Also, book a hotel in Machu Picchu for one night. Having trekked all that way, you'll be really glad for a bed and shower afterwards. You can also revisit the ruins the next morning.

Machu Piccu Hotels Guide

Walking the Inca Trail was one of the best experiences I've ever had. A wonderful memory, which was really enhanced by the tour company who where www.sastravelperu.com

The food was great, and staff, both porters and guides, could not have been more helpful. I'm not very fit, but I made it! We did the walk at New Year 2 years ago. It was safe, but very wet!

Thanks for the help guys!