library(RODBC)
file.name <- "file.xls"
sheet.name <- "Sheet Name"
## Connect to Excel File Pull and Format Data
excel.connect <- odbcConnectExcel(file.name)
dat <- sqlFetch(excel.connect, sheet.name, na.strings=c("","-"))
odbcClose(excel.connect)
Personally, I like RODBC and can recommend it.