ふん is the only correct reading for that kanji when it is being used to mean "minute".
HOWEVER, the sound of the ふ soft voiceless "fu/hu" changes depending on what sound comes before it, by adding a ゜semi-voicing marker making it a harder ぷ "pu" sound voiced more by your vocal chords. The sound of the end of the number and the beginning sound of ふん are contracted (merged/slurred together) to make it easier to say 分 with some numbers.
いち + 分 = いっぷん "ippun"
に + 分 = にふん "nifun"
さん + 分 = さんぷん "sanpun" *
よん + 分 = よんぷん "yonpun" *
ご + 分 = ごふん "gofun"
ろく + 分 = ろっぷん "roppun"
なな + 分 = ななふん "nanafun"
はち + 分 = はっぷん "happun"
きゅう + 分 = きゅうふん "kyuufun"
じゅう + 分 = じゅっぷん "juppun"
I've heard that さんぶん and よんぶん seem to be used too, even by some native Japanese, as normally an "h/(f)" sound will change to "b" not "p" when it comes after ん. But I'm fairly certain ぶん is always incorrect for this word and ぷん should still be used after numbers ending in ん.
A different word also written as 分 is only read as ぶん. This word means things like "part, segment, ration, degree, ...".
And another different word also written as 分 is read only as ぶ. This word is used for various types of measurements--such as for percentages.
Hope that helps, and I wonder if anyone thinks differently about whether it is さんぷん or さんぶん? ^^
December 25, 2014 at 10:47am