Compose key on Windows

Though this is an old question, many others probably stumble upon it via a Google search. So about 4 years after it's been asked, I figured a few more options do exist. I couldn't test them all (at home I have no Windows but those for light and fresh air -- and at work I cannot access e.g. Dropbox to download the archives of some), but here's a short list:

• AllChars: Last updated in 2009, but still seems to work up to Vista. Additionally offers "macros", which one cannot disable or edit on Vista, so the pre-defined ones might get in your way (not that likely, but they might). Update: After having used it for a while, I encountered some strange effects I attribute to this app (as they didn't happen before I installed it). No pattern in regularity, but sometimes my keyboard seemed to be messed up, CAPS inverted, some keys not working. Might be something else, though – but I didn't have that before. Update 2: None of the side-effects encountered since I switched to...
• WinCompose: No extra gimmicks like macros or the like, but that's not what we're looking for here :) Seems to use the very same layout I'm used to on Linux. Need some longer testing, but after one day it's already my favorite candidate here. Edit: Half a year later, it's still my favorite. Easy to install, runs stable, no side-effects, simply great! Update: Reportedly works from Vista to Win10. Still happy with it 3.5 years later :)
• CKFW: Compose Key For Windows. Couldn't test it as I couldn't access Dropbox for download.
• Unichars: I didn't test it due to the restrictions listed in this blog (doesn't work with all programs).
• FreeCompose: Last release in 2011, though the dev claims it's still alive in the repos. It's supposed to work with most programs (PuTTY had trouble, but a patch is provided). Disadvantages: annoying beep when "composing", which cannot be switched off. Also compose sequences are not the standard ones. Advantages: You can define your own sequences, and the service can be de-activated while running (without exiting it).
• USCompose is an alternative US keyboard layout, including some compose stuff. Not always matching the Linux compose key sequences.
• Accent Composer: commercial; demo available. Not tried.
• Compose-Keys: Claims to mimic the Linux compose key sequences (I missed a few, and not all of them seemed to work; sometimes one simply needs to "try until they do". Well, I have the same issue on Linux sometimes ;) Freely available at GitHub.
• WebComposeKey: browser-based, cross-platform. Nice to learn what sequences are available :)
• DIY: Microsoft Keyboard Layout Creator

This should give anyone in need a few additional options. I wonder if MS will finally built this functionality into their releases, where it belongs (note the "if", not "when")...

There are a couple of utilities to emulate the Unix-a-like key composition chords under windows. Allchars is one, which is also F+OSS, though I've not actually tried it myself yet (it is one of the many utilities in my "to try later" bookmark folder).

On Windows, AllChars should do what you want. I have been using it for the exact purpose you describe for almost a year now.

Caveat: If you install AllChars and your keyboard starts to behave weirdly, try one of the other versions they offer, possibly the alpha/beta. They all seem to have different issues with the different versions of Windows out there. But one of them should work with whatever you use.