That's an Athlon 64 fella, that's EXACTLY the original affordable and well designed 64 bit Intel compatible CPU. (Intel's own Itanium does not count. Expensive and poorly supported except on the server end. Opterons and the desktop version of the opteron, the Athlon 64 were freakin AWESOME chips in their day (still are, technically speaking, since the X2 and X4 "Athlon" (not Phenom, mind you) are basically multiple core versions of the original 64 with some extra fixes thrown into the mix.) Yep, you're good to go for 64 bit partner. Have at it.

If you do encryption on it later, since its 64 bit, you should get good performance from AES as well as TwoFish, Blowfish and Serpent... basically the last 3 encryption algorithms were designed to perform well on 64 bit chips, not 32, AES does well on either. It may seem like voodoo to you now, but you may well recall this thread later when you decide to dabble.
Let us know how it goes.
Side Note:
If you are into buying pre printed cd/dvd sets, you can go to cheapbytes.com, or google whatever their new site is. They used to do 1.99 for a printed cd back in 2000, plus post shipping. If you want, some of us might be able to send you the right dvd. Where are you, geographically? (Don't want specifics, you can PM if you wish.) Someone might be able to mail you a livedvd with install capabilities so you can try it out with most of the software already on the disk. (Or you can pick one up if you live near any of us willing to burn you a dvd.) DVD itself at full retail runs between 45 to 65 cents, and postage ain't overkill.
Personally, I would start with something simple and fairly automated, Ubuntu and Fedora come to mind. Keep in mind that Fedora is completely free and experimental (update servers are heavily laden with users and fairly slow, your updates WILL crash fairly often, especially on dialup.) Ubuntu is faster, and the updates can be run overnight fairly reliably even on dialup. Most of the important ones are a few megabytes at best. Suse works great, but being KDE based, is fairly graphics and system heavy. If your little emachine can support more than 1 gig of ram (890 mb tells me you have 1 gig, and 256 megs is shared with your onboard videochip, this is how it usually works with dedicated motherboard graphics) and you can afford to go to 2 gigs or more, KDE is doable, otherwise, too heavy, stay away from Suse.
You can try Debian, Mint or some others, but those are less automated and require some knowledge and willingness to experiment or ask questions and learn. If you just want to hit the ground running with other people having done all the hard work, Ubuntu, Fedora or Suse will be your best bet since most of their work is automated. Suse has piss poor cryptographic support in the installer, or did in version 10. I haven't tinkered with it since. When I do I'll post more. I've used both Fedora (a real bitch until you learn to use UUID's for drive mounting, no /dev/sd* or /dev/hd* stuff there) and Ubuntu on test rigs recently enough to say they both are fun, but Fedora is more system heavy, Ubuntu, being more Debianish, is fast, and fun and has all sorts of other options that scale with your skill level. Not quite up to the level of Hardened Gentoo or Linux From Scratch (LFS) but very usable even for a total n00b. But you might want to consider looking up bandwidth prices in your area. Most dialup is 19.99/month, and most cablemodems can reach well into the hinterlands for about the same price... sometimes 24.99/month. I used to pay 14.99/month for rural cablemodem 3 or 4 years ago with NO download OR upload cap when I was on the coast. Any TV company will offer something along those lines. The only catch is cable companies won't let you run your own email server, but I somehow doubt you're at that level right now.

Second Side Note:
Check out these prices:
http://www.newegg.com/Store/SubCategory.aspx?SubCategory=5&name=CD-DVD-Burners&Order=PRICE If you can afford it, those are worthwhile. They usually do 3 day UPS for free on most computer parts.
Correction: Cheapbytes seems to be defunct now. Probably too many people with CDRW/DVDRW drives, stacks of blank disks and high bandwidth. Sorry about that. Still, check the rest.