i m using redhat es4 os. while booting up my kernel it shows all of my devices except my sound card. i m using creative sound blaster 24 bit sound card.so, i need this driver for linux. from where i can get it free or from which site i can download it free?

RedHat enterprise has support that you paid for with it. You can contact them, and they can assist you. If you didn't pay for RHES, you should load CentOS, which is essentially the same thing, but community supported.

Your sound drivers should already be present...can you play any sounds after you get logged in? That's another reason to load a different distro. RHES is more focused on 'servers', which don't really need sound cards, rather than workstations which often do. CentOS or another 'workstation-friendly' distro may be a better fit.

Can you post the output of lspci?

Output of the lspci is given below:

00:00.0 Host bridge: Intel Corp. 915G/P/GV Processor to I/O Controller (rev 0e)
00:02.0 VGA compatible controller: Intel Corp. 82915G Express Chipset Family Graphics Controller (rev 0e)
00:1d.0 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 04)
00:1d.1 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 04)
00:1d.2 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 04)
00:1d.3 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 04)
00:1d.7 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 04)
00:1e.0 PCI bridge: Intel Corp. 82801 PCI Bridge (rev d4)
00:1f.0 ISA bridge: Intel Corp. 82801FB/FR (ICH6/ICH6R) LPC Interface Bridge (rev 04)
00:1f.2 IDE interface: Intel Corp. 82801FB/FW (ICH6/ICH6W) SATA Controller (rev 04)
00:1f.3 SMBus: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 04)
01:01.0 Multimedia audio controller: Creative Labs SB Audigy LS
01:02.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
01:05.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)

Ok...the sound card is being seen. But I posted other questions as well, which you didn't answer. And did you try CentOS?