There’s been a flood of companies trying to use web technology to improve personal finance — bank account aggregators, social investment sites, and now SmartyPig, which is pitching itself as “the 21st century version of of a piggy bank.”

The goal, says co-founders Mike Ferrari and Jon Gaskell, is to help people save for specific goals, like a big vacation or or a shiny new gadget. There are a lot of people who need help to develop better habits; after all, the news is full of stories and statistics illustrating that Americans are much more adept at borrowing than saving.

At its heart, SmartyPig is a website where you set up accounts with West Bank for specific goals, then make automatic monthly contributions from your checking or savings accounts. Not only do users save up to afford what they want, they also earn substantial 4.3 percent interest rate (that rate will shift, of course). Once users meet their goals, they can buy whatever they’ve been saving for using a SmartyPig debit card, and will receive discounts of up to 5 percent if they buy from SmartyPig partners like Royal Caribbean, Best Buy and Home Depot.

Obviously, it’s already possible to save money with sites like Mint, but I think SmartyPig is the first to explicitly tie those savings to different goals. Even better, SmartyPig functions as a social network where, if you make those goals public, friends and family can provide moral and financial support. This is a great idea, since there’s nothing like peer pressure to encourage responsibility. SmartyPig provides a fun, easy and secure way to apply some of that pressure. (I’m speaking hypothetically here — when it comes to saving, I’m as irresponsible as most folks in their mid-20s. But hey, maybe I can change too. I’m thinking about setting up an account to save for a 3G iPhone, whenever it comes out.)

The Des Moines, Iowa-based startup launched a few weeks ago, and it sounds like SmartyPig users are already setting their sights high. The average goal is $6,200 saved over a period of three years.