Among all the resources you might use when discerning your vocation, you may find it useful to always keep in mind the importance of reading the Bible and the Catechism of the Catholic Church (CCC). For young people, you might find the youth version (YOUCAT) of the Catechism useful.
Sacra Virginitas - on consecrated virginity
Ad Catholici Sacerdotii - on the Catholic priesthood
Mulieris Dignitatem - on the dignity and vocation of women
Redemptionis Donum - to men and women religious on their consecration in the light of the mystery of the redemption
Pastores Dabo Vobis - on the formation of priests
Saerdotalis Caelibatus - on the celibacy of the priest
Lumen Gentium - on the role of all vocations in the life of the Church
Directives on Formation in Religious Institutes
The Contemplative Dimension of Religious Life
Verbi Sponsa - instruction on the contemplative life and on the enclosure of nuns
Conference of Religious England and Wales
National Office for Vocation - good resources on vocations directors for each diocese, various discernment groups across the country, very easily accessible information.
Vocation Office - Archdiocese of Birmingham - specific to the vocation to the priesthood
UK Priest - website for the diocesan priesthood in England and Wales
Come Follow Me - vocations in the Diocese of Portsmouth
Called Today - Vocations website for 10-16 year olds. This is a great website for introducing the different kinds of religious life to children.
UK Religious Life - information about the various forms of religious life, advice on discernment and links to religious communities
Council of Major Superior of Women Religious - for women looking for discernment resources, guides, and videos
Institute on Religious Life - their vocational terms glossary is very helpful for those who feel lost in the language of discernment.
For Your Vocation - has some amazing prayer and discernment resources.
VISION Vocation Network - for those in the US, the Vocation Match is a great place to start for those who are unsure of what kind of lifestyle and spirituality they are interested in.
Vocation.com - excellent Q&A section on many questions that discerners face.
Vocation Ministry - a guide to help those who are discerning their vocation
Steps of Discernment - this is a really good pathway guide to discerning your vocation and breaks it down into steps that are really helpful and is applicable to discerning any vocation
Six Principles of Discernment
Resources for Older Vocations - this is a website set up by a friend of mine that is a directory of religious communities that accept 'older' vocations (although in discernment terms, some communities consider you 'old' at 30!). Communities are listed by apostolic and contemplative, communities are international. NB: Only communities that wear the habit are listed.
Professions - this playlist is just of various religious professions and investitures.
Religious Communities - these videos focus on specific communities and give a particular insight into those communities. They are well worth watching, especially if you're still looking at communities.
Gloria Deo - this is a very beautiful DVD from the nuns of Tyburn Convent.
Light of Love - a beautiful film that documents the lives of religious sisters in several different communities
For Love Alone - a wonderful film about about Catholic women choosing Religious Life. It follows religious sisters across the United States and emphasizes the risks and the rewards of giving everything to God.
These are books I have read or that have been recommended to me by people who's opinions I trust.
A Right To Be Merry - Mother Mary Francis, P.C.C. This is a fantastic book, written by a late abbess of the Roswell Poor Clares. I have only read part of it but it is well worth reading and presents religious life very honestly and openly, and gives an amazing picture of the great joy of their life.
On the Religious Life - Dom Prosper Guéranger, OSB. I thoroughly recommend this to anyone considering the religious life. Dom Guéranger was a truly wise man and this book is just fantastic. It is quite a 'heavy' book, so not for light reading. It obviously has a distinctly Benedictine 'feel' but is equally useful for those who do not feel called to the Benedictine life.
Discerning Religious Life - Sr. Clare Matthiass, CFR. This is a book that serves as a guide to help young women in discernment
Called to Love - A Listening Heart: A Book of Catholic Poetry - Christina M. Sorrentino. This is a book of Catholic poetry on faith and discernment.