While Abhayagiri has accomodations for lay women and nuns, it is not a training facility for ordained women.
For those who would like to begin training and ordain as a Theravada Buddhist Nun, we have provided websites below from nuns' communities where you can find more detailed information about this process.
In our own lineage (the Theravada Thai Forest tradition of Ajahn Chah), there are Siladharas (Buddhist Nuns) training in England at both Amaravati Monastery and Chithurst Monastery. You can find more information about the nuns in England by visiting Amaravati's website or Chithurst Monastery's website.
The following websites will tell you more about ordination and training as a Theravada Bhikkhuni (fully ordained Buddhist nun):
The Aloka Vihara is currently located in San Francisco and you can find more information about them at www.saranaloka.org
Another place of training is Aranya Bodhi Forest Hermitage. You can find out more information about them at www.aranyabodhi.org
In Ontario, Canada there is a community for nuns called Sati Saraniya Hermitage and you can find more information at www.satisaraniya.ca
You can visit a website called the Alliance for Bhikkhunis at www.bhikkhuni.net
Twenty-five minutes south of Abhayagiri in Ukiah, California, is the City of Ten Thousand Buddhas (CTTB). This is a Mahayana Monastery in the tradition of Dharma Master Xun Hua and has over 60 Bhikshunis training on-site. You can find more information at www.cttbusa.org. For more specific information on monastic training at CTTB you can go to www.drba.org/sltp/monastery.htm
We hope these resources are helpful for anyone interested in visiting these monasteries or exploring the ordination process for women.