Setting a cookie with an array?

OK, here's a new one (for me)... I have (sometimes) an array (and sometimes, just a single variable), that I would like to set a cookie for as a "Favorite"... In other words, if you goto my website (http://www.joescanner.com/) and use one of the search pages, you get a <SELECT> box and in some cases you can select multiple items. I would like to remember which items are selected by a user, and with that users permission (by checking a box, more than likely) setting the cookie to remember which systems to select. Will I need to write (or borrow :) a routine to change the array into a string, and then parse the string back into an array once the page is loaded? Or does PHP have some magic formula that does what I am looking for? Also, to complicate things, not all pages allow multiple items to be checked, in which case I would want to use the first item (in the possible array). If I am not being clear, please contact me via PRIVATE e-mail and I will try to be more succinct. Thanks in advance for any ideas, or help. Joe