What does this mean? Is it drunkardness or what? The Apostles and other disciples of Christ were faced with these questions after the outpouring of the Holy Spirit. The coming of the Holy Spirit was in line with the promise made to the Apostles by Christ who would have encouraged them to remain in Jerusalem until they receive the power of the Holy Spirit (Acts 1:8). The Holy Spirit came on the pentecost day - the "fiftieth day" after the Sabbath of the Passover week (Lev. 23:4-7, 15-16).
What does it mean?
(1) Christ's promise to his disciples is fulfilled - God is faithful all the times. He remains true to his promises.
What does it mean?
(2) God is with us. He builts a shelter for himself among his people - in their hearts; hence we are called to be the temples of the Holy Spirit of God (1 Corinthians 6:19-20).
What does it mean?
(3) The Apostles and other disciples of Christ are empowered by the presence (indwelling of the Holy Spirit) in their lives. They are given various gifts through which they must serve the kingdom of God. The church is a gifted church which should be of service to God at all material times.
What does it mean?
(4) The Apostles and other disciples of Christ are not drunk but filled with the Holy Spirit.
What does it mean?
The Holy Spirit appeared in the form of a rushing mighty wind and the tounges of fire. Whilst the wind signifies the presence of the Holy Spirit in this instance, the tongues of fire symbolyses God's cleansing and judging power (see Matthew 3:11,12). The Holy Spirit is there to guide the believers as the first fruit and assurance of their salvation; but He is also there to convict the world of its sins. That is why we experience the guilt conscious each time that we go against God's will.
What does it mean?
(5) As the sign of being filled by the Holy Spirit in this instance, the Apostles spoke in tounges. And tounges in this instance refers to the inspired language which the Apostles were able to speak in the presence of different language groups and dilects; but each one thought that they were speak their native languages.
What does it mean?
(6) The Holy Spirit inspired the Apostles to bear witness of the gospel and the mighty acts of God without fear (verse 11).
What does it mean?
(7) Where the Holy Spirit is at work, people never stop to be amazed. Verse 12 says: "all were amazed and perplexed, saying to one another, "What does this mean". Life filled by the Holy Spirit is a life of wonders; and to God be the glory in the church!

What do you do when you want to take a major decision in your life or any other decision for that matter. We normally rely on our wisdom or the wisdom of others without even consulting God in prayer. The Book of Acts in its entirety teaches us that we need to rely on the power and guidance of the Holy Spirit in every decision that we take in our lives as God's children.
Acts 1:12-26 teaches us the following:

(1) The early Christian church was a praying church. They met together for prayer meetings and were very consistent in that (verse 14). They were not lazzy or did not disregard meeting with other believers for prayer;
(2) They were very specific in their prayers - they had specific prayer requests offered, in this case it was the replacement of Judas as an apostle.
(3) Their prayer requests were consistant with God's revelation in Scriptures thereby reminding us that we need to pray acording to God's will. God's will in this instance was for Judas to be replace. Judas was a man who, even when he had the priveledge to be close to the truth (gospel about Christ), he was not necessarily committed or changed by this truth. According to the will of God, Judas had to be replaced (verse 20b);
(4) Praying according to God's will is also made manifest in that specific criteria for the replacement of Judas Iscariot was made - he had to be a person who was a witness of the ministry of Christ from his baptism until his resurrection. Eye witnesses were needed to fill the vacancy of apostleship. This in a way asserts the meaning of the word apostle which refers to those eye witnesses who are sent to bear testimony for the resurrected Christ in the world;
(5) In prayer, the early Christian church relied solely on the power and guidance of the Holy Spirit. They knew that it was God's work and therefore only God should make a choice as to who serves him in the capacity of being an apostle. 
 
We should therefore learn to rely on the power and guidance of the Holy Spirit in our lives as Christians. This will teach us to be a praying church that seeks God's face in whatever we go through in this world. We are not only expected to pray, as we rely on the power and guidance of the Holy Spirit, but also should pray according to God's will. God's will is revealed in Scriptures and therefore knowledge of the Word of God will help us to pray inline with what God really want from us. To God be the glory!