Installing a sound card has always been a tricky task, whether you used MS-DOS, Windows or Linux. In the age of the PCI bus and Plug & Play (PnP), things have become much simpler, except for the many owners of legacy ISA bus cards with or without PnP.
The first place to go for help should always be the book that comes with your Linux distribution. They are usually very instructive, and should be taken seriously and not ignored. If you still encounter problems, have a look at the HOWTOs mentioned below. Different users have different needs; therefore, we have at least three different sources for sound drivers, each one addressing a different group of users.
For industrial applications, it is important that the sound drivers support SMP (symmetrical multiprocessing). SMP allows Linux to schedule processes in machines with two or more CPUs on their main board. Most of the drivers already support SMP. The most recent versions of OSS and ALSA also support multiple sound cards in one PC. The ALSA project has received some funding from SuSE, and their drivers will be integrated into the regular kernel. This will not happen before version 2.5 (experimental) of the kernel.
Fortunately, the Linux community has produced some very helpful documents (see Resources). Read them; you will benefit, and each one deserves to be read. There are also many applications (mixers, recorders, players, converters, synthesizers) available for free (see Resources).