TFC's site is pretty good at giving market info: http://futures.tradingcharts.com/marketquotes/

It will give you the contracts for each commodity you're interested in. As a rule of thumb you're probably interested in the month with the highest volume, but there is the odd exception (ie. Eurodollar where the front months are the most liquid but are making the smallest ranges and the further out months are the ones with the better moves).

Most contracts trade in quarters: March, June, September, December. This is the case for the currencies, most of the grains, most metals and softs. The meats are the odd ones out and will trade every month of the calendar, but different meats will have different months.

For example, the most popular months for Feeder Cattle are: January, May, August, and November; but Live Cattle trades: February, April, June, October and December.

If you keep an eye on volume and open interest (relative to the other months available) you won't go too far wrong. Just remember that the closer months tend to move more than the farther out months. It's like tossing a pebble into a pond. The biggest ripples come first and the further out the waves go the smaller the impact. Futures contracts are the same. Knowing this can help you find a market with ranges you can afford as well as helping to manage volatility.

Erich