The inherent problem with SBLive! cards is that they don't have true DSP, so you'll almost always get some sort of latency. This can also be dependant on how much memory you have, what software you're running, how fast your hard drives are, and to a slightly lesser extent, how fast your processor is.
The two "quick-fix" tips I can give would be to make sure you have at least 256MB's of RAM, 512MB's would be better. And make sure you have the fastest hard drives you can afford, in the sense of ATA transfer speeds. ATA/66 is good, ATA/100 or /133 is much better, and you should have 7200rpm (spindle speed) drives. Take into consideration what kind of motherboard you have, because if you have a mobo that only runs at ATA/33, you're only going to get 33mbps out of your hard drives, even if they're rated for ATA/100. You could always put a hard drive controller card (preferrably not RAID, as digital audio doesn't get along with RAID striping or mirroring very well at all.) Promise and Adaptec make some of the best controller cards, and the fit into a PCI slot.
Also be sure to check the connections on your hard drives, and make absolutely sure that you're using UltraATA cables if you're using ATA/66 or faster drives. Don't use rounded IDE cables as they tend to corrupt data and don't use removable drive bays if possible (although if you have to, make sure they're rated for ATA/100.)
The best, and most expensive, fix would be to get a pro audio soundcard. M-Audio makes the Delta line and they start at around $300, with very good sound quality. If you can afford it, get a sound card with onboard DSP, which will reduce the latency to almost zero. Aardvark and RME make great cards, although they tend to start around $600.
If you post your system specs, I might be able to give you a few more tips. Hope this helps!