In-app purchases for upgrades, virtual goods and more, are an increasingly popular way for developers to monetize mobile applications, as opposed to making the app a paid download. This is especially true for Android, where paid apps don't perform as well.

In addition to the programs provided by platform makers like Apple and Google, there are a number of third parties that offer similar services. In this week's ReadWriteMobile poll, we want to know which programs you've tried, which you use and which you like or dislike.

In the poll below, we've listed several of the companies offering solutions for implementing in-app purchases within your applications. (Note that this is not a comprehensive list.)

Check off the the services you're using now and then proceed to the comments to share additional thoughts on whether the program is any good, and if you would recommend it to others. If you've had a bad experience with a company, let us know about that too.

And if we forgot a company, add it to the poll!