Here you will find some outstanding and easy-to-grasp instruction by outstanding dharma teachers such as Ajahn Brahmavmso, Bhante Vimalaramsi, Acharya Buddharakkhita, Ven. Dhammarakhita, dharma teacher Gregory Kramer, and Venerable Sujiva.
Like the facets of a diamond, each teacher's talks highlights a different aspect or way into the practice of loving-kindness. There's even an article on teaching metta to children! And if you already have a loving-kindness practice, I think you will still find many skillful and useful insights into how to expand and deepen your metta practice.
So please stop by: Metta Instructions and have a look around!
For more in-depth dharma articles and instruction, visit: METTA REFUGE