Aartis are the verses or sonnets (poetic or lyrical), in the introductory or in the form of praise of a God. Chalisa is a form of a prayer in Hinduism, in which there are forty verses in praise of the God. Chalisa of different deities are very popular among devotees and it is believed that a common man can get the blessings of his deity (God) by reciting the Chalisa with devotion. Chalisa means "forty verse" prayers. Verses that praise and plead with devotion. Look for a huge collection of chalisas -
http://goddess-durga-puja.blogspot.com/
http://shiv-bhajan.blogspot.com/
http://shani-dev.blogspot.com/
http://ganesh-aarti.blogspot.com/
http://sai-baba-bhajans.blogspot.com/