How can I get Kies to detect my Galaxy S GT-i9000 on Windows 7? When I connect my phone to my Windows 7 PC the Kies application opens and displays "Connecting", but it does not connect. Why? How can I fix it?
This answer doesn't seem to apply if you have a Galaxy S running the official Froyo, and the latest Kies as they seem to have fixed many of these issues now, this is mainly for if you're running an older phone OS or Kies version.

For prior versions of Kies and the Galaxy S (I don't know which upgrade is the one that fixes it) there were quite a few problems Kies had seeing phones.

Some of these problems were driver problems, you can generally fix these by using the reinstall drivers option in the Kies menu at the top-left of the Kies screen.

Kies had problems connecting properly to phones that had files on them with long file extensions (I think the problem was  if they were 16 characters or longer, but I couldn't be sure).

To get round this problem, firstly if you have an SD card in your phone, unmount, eject and remove it for the moment, this saves a lot of messing around with the contents of that card, you can plug it back in after you've done everything you need to in Kies.

Next attach your phone to your PC in Mass Storage mode, and have a hunt round on the internal SD card and internal memory for groups of files with long names and long file extensions (one particular culprit is often the pictures' thumbnails cache which sits under Android\Data\com.cooliris.media on the internal memory; you can safely delete everything in that folder, it'll get automatically regenerated next time its needed). Once you've done this, disconnect from the PC, run the My Files app, and go in and re-delete that folder if it has regenerated (if you haven't got My Files you should be able to find it in the Samsung Apps listing, if not you can use something like Astro File Manager).

Finally make sure you are actually connecting to the PC in Kies mode. depending how your phone's set you may get a list appear on the phone's screen when you plug it into your PC asking what mode to connect in, make sure you select Kies mode. If you're not seeing that menu and its automatically connecting in one mode or another, then you can go into your settings and re-enable that menu. On a Froyo Galaxy S (it was somewhere slightly different on Eclair but I can't remember where) go into Settings -> Wireless and Network -> USB Settings, and select "Ask on connection".

Of course this all depends what you want to use Kies for, if you want to backup files from the phone, look up contacts, send/manage text messages, etc then it might be worth trying out the Kies Air app that Samsung released into the Samsung store recently, this runs a website on your phone that you can connect to from a PC using your web browser over the wifi connection, this smooths out almost all of the connection problems and is actually quite a nice, handy piece of software.