The info you are going to need depends on the type of targeting and link building method you are using for your link request but in general you will need the following information:

You will need the email address of the given site

Visual confirmation that a link to a given site is still there if you are planning to send emails mentioning that a given site is linked to.

Visual confirmation that the site is still active, alive and worth bothering with. Don't believe all links reported by google are going to be as described. Scan them quickly.

Visual confirmation if special link trading instructions are presented on the site. If they are you will have to save such link requests for another time apart from your lage scale mass link efforts. Links are usually on a link page so this sort of things should be obvious if present.

To make a link request you first need to find the email address. Many sites do not put contact info on every page so you might have to go to the home page section of the site or the highest point in a given directory if the site is on a free host. If you see no email address at freehost.com/somesite/cars1.htm you might want to edit the url to freehost.com/somesite/ and see if you can find an email address there. If this does not work you can use google itself to search the given url for the phrase email address. It is far easier to do this if you have the Google Toolbar if you don't you can download it from http://toolbar.google.com/ The toolbar will enable you to easily search a given domain as you are viewing it for phrases like email address. If you are at somesite.com/strangeobscurepage/page3.htm it might not be so easy to find the site's email address but if you have the google toolbar you can just type Email or mail and search the domain you are at. You also can gather email addresses for link request sites by looking at the contact address of the owner of the website domain. You can do this by going to a registrar like Directnic and doing a who is search for the domain you are interested in learning about in the format domain.com With email addresses obtained in this fashion you might want to reserve these link request offers for a more personalized email.

1 Dead url no content on link page while the rest of the domain is active

2. Dead url no content on link page and the entire domain is dead

3. Live link url altered which no longer includes a link to the site you thought they did.

4. Live Link url with no email address on link page

5. Live Link url with contact possible via form email only on link page

6. Live Link url with email address presented via mail box icon or graphic

7. Live link url with email address presented via email address in proper format webmaster@example11strangesite.com for example

8. Live Link url with email address presented via anchor text such as contact which then links to the email address.

9. Live Link url which is part of a directory of sorts with specific submission requirements

10 Live link url on a page which requires reciporical linking

11 Link page has exact same content as several other link pages on your list; these are mirror sites.

12 Link page url with preachy anti spam message. Be very careful with these even if you plan to send a very personalized email!