Most wine tastings are given by local wine merchants or clubs and are often educational in nature, meaning they are workshop-like and lead by a speaker; some sort of professional in their field. Liquor and wine wholesale distributors, liquor/wine shops, usually hold them; or even restaurants that may be introducing a new wine list.
The tasting will likely have a theme (a grape variety, a region, a comparison of two or more wines, etc.). You’ll probably be seated at a table with several glasses in front of each taster in order to sample the different wines being presented. Each taster should have glass of water as well, to cleanse the palate between wines. There is often a bucket of some sort on the table, too, for those who wish to spit and not consume everything offered.
These “workshops” are generally excellent ways to broaden one’s viticultural knowledge. They are a good way to decide what you like and don’t like, and to sample wines you may not have considered before. Tastings are often a relative bargain, too. They are sometimes even free (if a local distributor or wine shop has a special promotion going on or the like) or at least, low cost.
The expert conducting the tasting offers his/her opinions and knowledge in order to assist you in shaping your own judgment of what appeals (or may not) to you, the taster. They may offer up a question and answer session before, during, or after the tasting. And do ask if you are comfortable in doing so. The speaker is there for you, the sampler, to explain things in depth, clarify something you may not understand, etc. if you require more on the topic of what he/she has spoken about. They are there to expound on their areas of expertise. That’s the whole purpose of the tasting, to sample new and different wines and learn something in the process. This is spoken as someone who’s conducted a few, and attended way more than that.
Another bonus of attending a tasting, you are able to meet and socialize with other lovers of the grape. This may lead to formations of new wine clubs and may help with sharing the expenses of cases of wine if the tasting makes purchases of wine possible.
I’d love to tell you more about the tasting itself, (and I most definitely will at a later date), from the setting, to the order of the wines that are poured, scoring the wines, decorum) If you get the opportunity to attend one, by all means give it a whirl. They are fun, entertaining, and a good learning experience.