Hadith 628
Sayyiduna Abu Hurairah (may Allah be pleased with him) says: I saw the Prophet (peace and blessings be upon him). He (peace be upon him) was drinking Zamzam water while standing.
Hadith 629
Sayyiduna Ibn Abbas (may Allah be pleased with them both) says: I gave Zamzam water to the Prophet (peace and blessings be upon him), so he drank it while standing.