Bad news, the only way I've managed to get OS X to work with the sea slug is to plug it into another computer and run some sort of proxy software. I use Windows 98 and winproxy, it works quite well and it let's you share your connection with more than one Mac.
The reason I had to resort to this is that Alcatel still dont have drivers for OS X, but good news is on the horizon according to http://bbs.adslguide.org.uk/ the drivers should be out at the beginning of November.
Release 1.4 of modem ADSL increases ease of installation
Paris, October 16, 2001 - Alcatel (Paris: CGEP.PA and NYSE: ALA), the world leader in Digital Subscriber Line (DSL) and broadband solutions, today announced a new driver set for its Speed Touch (TM) USB, release 1.4 . Next to the introduction of support for Windows XP and Mac OS X, the latest Operation Systems versions for PC and Mac, it also eliminates the need for an additional PPPoE client, for those networks running PPPoE.
The Speed Touch (TM) USB is the easiest-to-install ADSL modem in the industry, and is ideal for single-PC or PC-gateway networks, typical for residentials, SOHO (Small Offices/Home Offices) and small companies. An integrated PPPoE-client on the modem avoids having to install client software on the PC itself, increasing ease-of-use. Due to installation costs, OS upgrade problems, and instability of the PC, software installed on PCs can be quite a deployment hurdle .
When released in mid October, the new software will be shipping with the hardware, and will also be available as an upgrade, downloadable from http://www.alcateldsl.com, free of charge.