I have a program I wrote and I have been encouraged by folks to release it into public.
What would be the best way to go about it? Just dump it on a public site and hope for the best?
How much criticism will come (on the standards, decisions made etc...) and how best to prepare for that. I have been the sole developer for this app for about two years.
And how much difference does the license (GPL, MIT etc...) practically make?
Any experiences?
A license is a good idea, even if you don't care what people do with the code - most of the time people will happily take code "as is" and if it doesn't do what they want they will just throw it away - but you never know when some idiot might try to sue you because they burned their mouth drinking a hot coffee while reading your code. You may also wish to restrict usage (derivative works etc) where someone else makes profit out of your hard work. Fron the other side of the fence, people who might take and use your product/code like to know where they stand with regard to use/copying/distribution. By asking that your name stays on the code, you can also ensure that you get vcredit for the work, and that any improvements/suggestions that happen in the wild can make their way back to you.
If you just want to give away the code wihtout much ongoing development, then a great place is CodeProject - you can release the application and write a small article describing it, and then it's up to you to decide if/when you will post updates.
If you want other people to collaborate then there are plenty of open-source websites that will support this approach.
As for criticism, you are likely to get a few mails from people who need tech support, or who want to suggest extra features. Most people are very polite though. If you wrote the program for yourself, there is a good chance that when it gets into the wild you will discover all the bits that have to be used in a particular way to work well, and all the additional options that you don't care about but which the product needs to make it applicable to a wider audience - you can get sucked into a lot of support work if you're not careful. Ultimately don't be afraid to say "no" to someone if they ask for something you don't want to support - it's your program and your time after all.
The main thing is to have fun :-)
CodeProject is a good suggestion- but it really depends on the platform. Typically users of each major development platform flock to other sites for their Open Source extensions or apps. For example, lots of developers on the Microsoft stack look for things in the Visual Studio Gallery or on CodePlex. SourgeForge obviously has its own religious following as well. I would suggest promoting your new app on a site where you would go to find something like it. The Google page rank of whatever public site you use to host it will also impact how many people find it and ultimately how much criticism (constructive or otherwise) you get on the project. Licensing is always a good plan. It has been my experience that each major open source collaboration site tends to learn towards a specific licensing mechanism, so I would just do what seems to be the most popular if you don't have any specific requirements.
Using a well-known, well-tested open-source license will make it easier for your users to know where they stand with regard to your code. The worst thing you can do is release your code without a license. No license means no use, since in most jurisdictions software is automatically copyrighted with no right of use or reuse.
If you don't want the project to wither away from lack of interest, you'll need to get it in front of developers. Releasing it at a large open source project site (such as SourceForge, GitHub, or Google Code) will help you get that visibility, and will provide a lot of infrastructure for managing your project. The more you do, the better the chances that others will find it, try it, and use it.