Have one I can email you.
No offense intended but I wouldn't take that on a dare...
If you want a keylogger, the way to get one is to BUY one. eBlaster, Webwatcher, Spector Pro, Family Keylogger...
There are some that allow remote installation via email. But these can normally be found by anti-spyware scans and some of them will be blocked and flagged during installation.
For desktops, the simple hardware loggers work well if you can get to the machine to check it out. To get into a laptop you need more than anything else, time. Given enough time, you might be able to hack your way into stuff.
But if she/he uses web-based email (yahoo, MSN, Live, mail.com, gmail etc, you should be able to get into her account without actually using her machine. Unless she/he uses Outlook/Outlook Express to pull pop-mail from a server (which I do myself most of the time and let the messages on the server be deleted) you can read her/his stuff just by getting into her/his account.
Here's the thing, a keylogger will tell you the passwords and what they are doing online other than emails. But if you can find the email account and get into it, you will have enough to bust things open.
Seldom does a wayward use secure enterprise servers for an affair. Seldom do they leave copies of things on their hard drive. They KNOW those things will get them busted sooner or later. But folks who use web mail solutions almost never consider that anyone can actually tie them to stuff left lying about. And THAT is where the weakness that can exploited comes into play.
Try hacking in a few times and if you can't guess passwords, give it a break and try again later. If you think long and hard enough, you should be able to guess many passwords. People never use RANDOM keystrokes as passwords because they can't remember them. a passward is something that means something. Find it and you're in.
Then READ the emails (including trash, personal folders, inbox, outbox etc. Never delete a message, add a message or comment in person about a message or your access will be gone and the account might end up moving.
Affairs are usually run using the free disposable servers and using a pure web-based account.
Hack your way in and you don't need a keylogger.
Fir IM you need a keylogger.
Keep in mind that many of the parental control programs that log activity will give you what you need and some of these are pretty cheap.
Want a keylogger, get one from someplace you chose to get it from, not from someone random via email.
Might as well send the reports to adtracker yourself...