AES Crypt is a specific product with a defined file format. Many tools implement AES, but they're not all compatible with AES Crypt.
The current AES Crypt for Windows still works; I use it all the time. That said, I am working on a new v4 right now to make various improvements (mostly under-the-hood things, including stronger security and speed enhancements). The Windows version, Linux command-line and GUI packages, and Mac command-line versions are all done. Mac GUI version underway now. Code is undergoing constant testing (literally running 24x7 doing a variety of tests to ensure everything is working properly). The Android and iOS developers are also on board to revise their applications to align with the new v4 coming.
The new version for Windows will probably be 64-bit only (targeting Windows Vista or later). I do not think many use the 32-bit code anymore, but I'm that is incorrect, then I'll work on that build.
As before, all code will be published, so people can review, critique, and have available if, for any reason, support no longer exists. There is no anticipated end to support, though. The only reason it has not had a significant update for so long is that "it just works."
Plus, as you can appreciate, there's a lot of work moving from one major release to anther across all platforms. The good news, though, is there is actually a common codebase for all platforms. It was a lot of work, but I think the common architecture and code is a huge improvement.
I am not aware of any online sites that provide online decryption, but being paranoid with passwords, I would not trust one if I saw it. Anyway, since the source is published (and will be with v4), there's not much to worry about in terms of not having the ability to at least decrypt at the simplest level (e.g., Linux or Mac command-line).
