Be sure this is not part of a scam. I've gotten this email a few times (for domains that obviously aren't worth that much). How it works is they ask you to get the domain appraised, steering you into some bogus appraisal company they run. That usually runs about $100 bucks or so, and they'll run off with your money and never hear from them again.
Here's the scam email I received once:
We are going to purchase your domain name.
Our company is in hosting and domain name business.
Please email us your desired price in USD or euros for the domain name
in the subject line.
If you have other names for sale please email us your domains with
Looking forward to doing business with you.
Domain Investing Inc Domain Name Investing & Web Development
I then wrote back with:
Hi - I have the following domains I'm trying to get rid of:
various domains I owned at the time
Whatever you think they're worth is fine with me. Thanks!
To which he replied:
What do you think about 4000 USD for your domain name? This domain
name can be very profitable with right marketing.
Have you had your domain names evaluated in the past? I mean domain
appraisals. Without valuation we cannot be sure in the sale price.
It's very important for me in terms of reselling too. But we must
engage a valuation company with REAL manual service. So I will only
accept valuations from independent sources I and my partners trust.
To avoid mistakes I asked domain experts about reputable appraisal
companies. Please check this blog with suggestions from other sellers
and buyers: http://www.thenamepros.com/Archive/94140683.htm
Do you sell domain with a web site or just the name?
Domain without content is ok with me. Web site is not necessary.
If, for example, the valuation comes higher you can adjust your asking
price accordingly. It will be fair. I also hope you can give me 12% -
After you send me the valuation via email (usually it takes 1-2 days
to obtain it) we'll continue our negotiations.
What is your preferred payment method: Escrow.com, International wire
transfer, PayPal.com or something else?
Hope we can come to an agreement fast.
When I asked him which domains he wanted to buy, he said all of them and provided a link to where I could get them appraised. Of course I did a WHOIS on that link, and it had similar registration info as his own email domain name. Go figure.
I replied and said I'd take whatever price he was willing to pay (since I was going to let them expire anyway), but I would not pay to get them appraised. Never heard back.
Don't pay a dime out of pocket, if someone wants to buy your domain let them make an offer and take it or leave it.