library(RCurl)
library(rjson)

hashtags <- c("%23cagov", "%23cagovdebate", "jerry+brown", "meg+whitman", "brown+whitman", "%23cadebate")
for (i in 1:length(hashtags)) {
    for (j in 1:10) {
        text <- getURL(paste(c("http://search.twitter.com/search.json?q=", hashtags[i],"&rpp=100&since=2010-10-13&until=2010-10-13&page=", j),collapse=''))
        entry <- fromJSON(text)
        print(entry)  #DO SOMETHING... here we just print
    }
}

#or

for (i in 1:length(hashtags)) {
    for (j in 1:10) {
        entry <- fromJSON(file=paste(c("http://search.twitter.com/search.json?q=", hashtags[i],"&rpp=100&since=2010-10-13&until=2010-10-13&page=", j),collapse=''))
        print(entry) #DO SOMETHING... here we just print
    }
}