How should I save my old emailed love letters?

You didn't tell me what email program you use. Some of what I'm going to suggest will be easier in some mail programs than other.

But here's what I would do: "print" those letters to PDF, and then copy them to another computer, or better yet, archive them by burning them to a CD.

First, if you don't already have it, I'd grab a copy of the free, open source PDF Creator. This installs a printer driver that, when you print to it, creates a PDF of whatever it is you're printing. It's extremely useful and in fact, in a move to reduce paper consumption, is my default printer.

Now, in your email program, just print one of your emails. The result will be a PDF of that message.

In order to avoid having to do this 400 times, your email program may be able to help you, if it supports what I'll call "multi-select printing". The concept is this: while looking at the list of messages in your inbox, you click on the line representing the first message, and then you CTRL+click (hold down the CTRL key while clicking) on another. Both are selected. You keep CTRL+clicking until you've selected all the messages that you want to print. Then invoke your mail program's print function, and see what happens. In Outlook, for example, this resulted in a single printout of all the selected messages. Sadly, in Thunderbird, this resulted in a separate printout for each message. In other mail programs this approach may not work at all, but it's worth a try. (Imagine my surprise when I discovered that MSN Live Hotmail does this properly - though there you use the checkboxes to select messages and then use Hotmail's print function.)

The reason I recommend PDF format is simply because it has become so ubiquitous and so many professions are now relying on it, that I believe that support for viewing PDF files will be with us for many, many years. The same is not necessarily true for whatever storage format your email program happens to use. Will computers 25 years from now still have software that can read Outlook Express mail folders? Given that computers today often have trouble with it, I suspect not ... or at least not easily.

Once you've created the PDF(s), I would then transfer them to a new computer, and of course back them up. Ideally I'd burn them to CD and keep that, or a couple of copies of that, in a safe place.

If the PDF approach doesn't appeal to you, there are other approaches.

Copy/Paste, as you say, is an alternative, but a slow one. You could, one by one, copy the letters to another document, perhaps Microsoft Word, and then save that.

Another approach is to see what alternatives your email program provides in the way of "Save As...". You may be able to simply save each message to disk in standard format. In the best of all worlds, you may even be able to use that multi-select method mentioned above to actually "Save As..." multiple messages into a single file. (Microsoft Outlook would do this, Thunderbird would not, your email program may or may not.) Particularly, if you can save multiple messages into a single file, it's possible that you might then be able to open that file in a word processor to clean out unnecessary information like email headers that might well be present.

Finally, one alternative for the brave. And I'll openly admit this is a hack (geek speak for a solution that might work, but uses techniques that might be considered extremely inelegant and just not pretty). In some mail programs the actual storage file used for the mail folder may be enough. For example Thunderbird stores email in plain text files (it's one reason I chose Thunderbird). Make a copy of your inbox folder - never open the official copy in anything other than the mail program that created it - and open it in notepad, or Word or whatever you like, and you'll find all your email in a single file. Naturally, not all email programs work this way; Outlook and Outlook Express do not, Thunderbird and Eudora do, and of course this doesn't even apply to web-based email services where the email is stored on a remote server.

But in your shoes, it's a hack I'd try as well.

As you can tell, how easy this get depends a lot on the abilities of your email program. Given the importance of what it is you're wanting to save, I think a little experimentation might be called for to figure out the approach that works best for you.