HuskerBoard

Padded biking shorts are the way to go.

Came in to say what Knapp said. Invest in some good shorts. You will thank yourself. 

Same opinion as the other two - bike shorts. Get good ones. I actually had to get a new seat recently too because my bike shorts and seat were sometimes causing my groin to go numb, so I went with a new seat that has a divider in it.

Bike shorts and be sure to lube up. 

It's probably important to note that this won't completely solve soreness. Especially if you have a hard saddle on your bike, there's going to be some irritation. The best thing you can do is ride more. Your body builds a tolerance.