You may be noticing a trend: there are a lot of startups looking to mimic the easy-to-use development platform that made Heroku a hit with Ruby developers and offer a similar solution for use with other languages. In the last few weeks alone we’ve written about PHP Fog (which, as you’d guess, focuses on PHP) and dotCloud (which aims to support a variety of languages). And today we’ve got one more: AppHarbor, a ‘Heroku for .NET’. The company is funded by Y Combinator, and it’s launching today.

AppHarbor will be going up against Microsoft Azure, a platform that developers can use to deploy their code directly from Visual Studio. But co-founder Michael Friis says that Azure has a few issues. For one, it uses Microsoft’s own database system, which can lead to developer lock-in. And it also doesn’t support Git, which many developers prefer to use for collaboration and code deployment.

Other features: AppHarbor has automated unit testing, which developers can run before any code gets deployed (this reduces the chance that they’ll carelessly deploy something that breaks their site). The service also says that it takes 15 seconds to deploy code, rather than the fifteen minute wait seen on Azure.

Friis acknowledges that there are a few potential hurdles. For one, some .NET developers may be used to life without Git, so it may take some work to get them interested (Mercurial support is on the way, which many .NET developers already use, so this may not be a big deal). There’s also going to be competition for the small team, which currently includes Friis, Rune Sørensen and Troels Thomsen.

AppHarbor is first to launch, but there will be others: Meerkatalyst and Moncai are both planning to tackle the same problem, and they won’t be the last.