Hi Chris and welcome to DNForum.
Glad you are not afraid to ask questions about the domain business.
Pool is www.pool.com and is an Internet business consisting of a number of registrars who work together to snap up expired domains and sell them to anyone who wants to buy them. If you are the only one wanting to buy the name you get it for a fee of $60. If others want it as well then it goes into an auction and, guess what, folks can get carried awy and boost the price through the ceiling! There are a number of similar services from Snapnames, Namewinner, TheFirstName and others but Pool seems to have the most resources and so generally the greater success (although care is needed not to get charged for names you didn't order!).
Enom is www.enom.com they are a registrar where you can register domain names, generally at reasonable prices. Accounts from them can be obtained to buy names at $8.95 from any Enom reseller - some can sell you an account to buy names at $6.95 but those accounts usually change hands for over $300 each and are no longer available from Enom unless you deposit $6995 with them. Many resellers like Enom because of its useful reseller contol panel and features.
TM issues mean that there are trademark issues involved with a name that could get you into hot water with the trademark company. So for example if I offered to sell you microsoftsoftware.com and you bought it, you would likely end up with a C&D letter (cease and desist) from Microsoft's lawyers and possibly a huge legal bill to boot. Some resellers accept the risk of TM issues and don't get challenged, but if you are a newbie to the game, best to avoid these. If it sounds like a well-known company then better do your research and consult your lawyer before you buy/reg it.
Hope that helps, and again, welcome.