I'm a big fan of the Planning Poker technique for estimating. It basically is a process where everyone in the room gets together with cards and estimates effort for user stories. Each card has a number on it (a modified fibinacci sequence) of 0, 1, 2, 3, 5, 8, 13, 20, 40, and 100. Then everyone reveals their estimate for a given story at the same time. Any estimates on the fringe are challenged and justified and an estimate is arrived, then the process is repeated for the next user story.
Mike Cohn and the Mountain Goat Software people have put together a fabulous website to solve a problem with planning poker, that is the one of remote users. It doesn't help planning poker if the users are off in another city so planning poker, the site solves that. You create an account (free and only requires 4 fields of information) and log in. Then someone creates a game and everyone participates online. Its a great way of doing this, and you can export the results to HTML and CSV at the end of the session. There's even a 2 minute timer that you can invoke once you've discussed enough about a story and a ready to estimate. Some people have even used it internally by everyone bringing their laptops to the session rather than even using physical cards.
So check out Planning Poker for yourself as it might be useful in your next planning session. Here are some screenshots that walk you though creating user stories and estimating them with the planning poker site.
When you log into the site you can view the active or complete games. Complete games can be re-opened if you need to do them across a few days:
To create a new game, click on the link and fill in the name and description. If you have stories already ready to estimate, you can paste them into the field here from a spreadsheet. The first row should contain the field names.
To add a story for estimating, just enter it in the form As a/an <role>, I would like to <function> so that <business value>. There's also room for notes that might be something you want to capture but make it light, this isn't the place for requirements gathering details here.
Once you've added a story, the estimating game begins. Select a card from the screen for that story.
Then you can accept or play again with that estimate. Your estimate shows up along with others (if they're logged into your game).
If you were wrong with your original estimate or there's debate on something and you really do agree it's larger/smaller, click play again and select a different estimate.
When all the estimates are done and the game is complete you can view all of the estimates online.
Finally if you want to take this information elsewhere, you can export it HTML for viewing/publishing/display or to a CSV file for importing into another tool.
Note that Planning Poker doesn't work very well under IE7 on Windows XP but the guys are working on it. I flipped over to use Firefox for the screenshots and use FF when I do my sessions using the tool.