Livemocha and Babbel are two fairly good websites that I can recommend for those of us wanting to increase our knowledge of Spanish past 'olé' (^_^)
Registration is free with Livemocha but to participate in lessons or courses, you have to purchase beans. During the course of learning, you also accumulate points which helps you move onto the next lesson. Native speakers (teachers, language experts) will leave reviews on your online exercises and I find this very useful for both written and verbal drills, and to distinguish between formal and informal speech.
Registration is also free with Babbel and a free first lesson is offered. In order to continue with lessons or courses, you need to register on a recurring payment plan.
Of course nothing beats learning with live native speakers. Edmonton Spanish Speakers and Spanish in Edmonton are two groups that are quite actively involved in helping others learn Spanish in a fun, casual environment!
Please feel free to share resources or other avenues that you can recommend to learn español!