Ing manages my 403K at work. http://www.ingretirementplans.com/index.shtml
under tools and calculators, click the "Income Wizard". This will help you out.
I'm in the middle of taking a class "Aging and Society" and the outlook for the next generation of retirees...the baby boom.......and there are lots of them........looks grim. 1/3 of them don't safe anything. 1/3 save some, but not enough. 1/3 are looking towards retirement with some sort of plan. That means the generations younger will have to support a large number of poor older folks.
I'm a late bloomer. I didn't start saving for retirement until my 30s and have enough maybe to live one or two years in comfort. But I hope to work for 20 or more years to remedy that.
Other countries are fairing better. The Koreans save a whopping 25% of their income, with Japan saving about 15%, Europe 10%. Americans save a useless 1 to 2%. Countries such as Austrailia and Chile have great plans while America sleeps and spends.