The best way to answer this question is to look for salary surveys online. Microsoft and Cisco occasionally fund such things because of the popularity of their credentials, and you'll also find annual cert-related salary surveys at Certification Magazine (www.certmag.com) and CertCities (www.certcities.com). My gut feel is that both MCSA and CCNA are considered entry-level certs and as such don't really do much to boost salaries for individuals who occupy the junior or mid-level system and network administrator positions most likely to at least understand and "get" the value of this certifications, even if they don't require them from all prospective job candidates.
Because salaries vary so much by region and location (think New York City versus Boise, Idaho, for example) it's meaningless for me to give you any numbers. All I can say is something probably not less than $30,000 per year nor more than $85,000 per year for an individual with both MCSA (on Server 2003) and a current CCNA, depending on location.
Turn to the surveys, which are regionalized and often also provide information about major metro areas separately. If that doesn't work for you, you can get a tailored analysis from Foote Partners (www.footepartners.com) for $200-300 that will tell you exactly what you want to know with a great deal of specificity, currency, and accuracy.