I'm finding all sorts of useful posts in the blogosphere about the upcoming feast.
Fire of Thy Love writes about its Jewish roots: "The Jewish people celebrate on Shavuot the day that God gave the Torah to His people. On Pentecost, we celebrate the day that we received not only Torah, but the divine author of the Torah, the Holy Spirit"
OSV has a sweet video from Busted Halo.
Abp. Dolan wishes us all a Happy Birthday.
Msgr. Pope offers us a pep-talk of sorts.
Catholic Culture provides a link to this homily, which lists the many ways we encounter the Holy Spirit on a regular basis.
Beginning to Pray has a lovely spiritual reflection posted.
Fr.Z is praying this Novena to the Holy Spirit. Happy Catholic is praying it too, and hers is illustrated. You too can pray with the whole church in preparation for Sunday:
ACT OF CONSECRATION TO THE HOLY SPIRIT
To be recited daily during the Novena
On my knees I before the great multitude of heavenly witnesses I offer myself, soul and body to You, Eternal Spirit of God. I adore the brightness of Your purity, the unerring keenness of Your justice, and the might of Your love. You are the Strength and Light of my soul. In You I live and move and am. I desire never to grieve You by unfaithfulness to grace and I pray with all my heart to be kept from the smallest sin against You. Mercifully guard my every thought and grant that I may always watch for Your light, and listen to Your voice, and follow Your gracious inspirations. I cling to You and give myself to You and ask You, by Your compassion to watch over me in my weakness. Holding the pierced Feet of Jesus and looking at His Five Wounds, and trusting in His Precious Blood and adoring His opened Side and stricken Heart, I implore You, Adorable Spirit, Helper of my infirmity, to keep me in Your grace that I may never sin against You. Give me grace O Holy Spirit, Spirit of the Father and the Son to say to You always and everywhere, "Speak Lord for Your servant heareth." Amen.