Welcome to the Apple Support Communities
If you want, you can install iWeb. If you have bought a new Mac without iDVD or iWeb, you have to buy iLife '11 on a DVD on Amazon to get them.
If you don't want iWeb, you can find replacements > http://www.cultofmac.com/101080/three-popular-applications-that-can-replace-iweb -one-to-take-you-to-the-next-level/
Apple have not 'Done away with iWeb' as you put it. They are no longer supporting it and no longer upgrading it, but this DOES NOT mean that you can't still use it to create websites with.
Apple stopped supporting it sometime ago now, but it is an application like any other that you have and if you have it on your Mac, then you can still use it - it works with both Lion and Mountain Lion and if you want it you can still get it, but you'll have to purchase it from Amazon as part of either the iLife 11 or iLife 09 boxed set.
If you really want to use other software, which you don't need to take a look at RapidWeaver, Sandvox, Freeway Express and Pro 6, Flux 4 and Quick n' Easy Website Builder. Most, if not all of these have free month long trials where you can download and try before you buy.
As well as these, you have other options such as the online web site builders such as http://www.wix.com or http://www.weebly.com, or the CMS's (Content Management Systems) that you can install directly on your host/server and include http://drupal.org and http://joomla.org amongst others.
Rage software are also producing their own version of iWeb called EasyWeb - however, all first reports would seem to suggest that you won't be able to purchase this software on its own when it is released - it will initially be tied to Rage web hosting, so you would need to purchase this first to be able to use EasyWeb.
However, if you still have iWeb then use it for as long as it works and don't look elsewhere. Just because iWeb is no longer sold or supported by Apple does not mean that you can't still use it - you most certainly can.
Just a note on iDVD and installing on new Macs:
If one has to purchase an iLife disc they should be informed that iLife 11 only provides iDVD 5-7 themes. Software Update no longer installs the earlier themes nor do any of the iDVD 7 updaters available from the Apple Downloads website contain them.
Currently the only sure fire way to get all themes is to start with the iLife 09 disc:
This shows the iDVD contents in the iLife 09 disc via Pacifist:
iWeb can then be updated from iDVD 7.0.3 to iDVD 7.1.2 via the updaters at the Apple Downloads webpage.