If doesn't matter if it's been awhile since you attended school. Taking a writing class can be a great option to keep up your skills. Here are a few ideas about choosing the best one for you:
1) Determine what it is you're hoping to gain...more technical skills, some networking, or just to be surrounded by other writers. This will help you decide how much time and money you're willing to invest.
2) Consider taking an online writing course. Most of these are aimed at the novice writer, though you can find some that cater to the experienced, professional writer. You'll find them genre-specific as well: romance, sci-fi, poetry, scriptwriting. This is a convenient way to network and give you a new perspective on the writing world. Just do your research and make sure the group is reputable.
3) You probably get one of those community newspapers in the mail from time to time. Open it up and see if there's a writing course available...there probably is. If there isn't, let your community college know and they might just add it to their next curriculum.
4) Workshops and conference can be found throughout the year, hosted by various writing groups. Again, they're probably genre-specific and will cost a bit of money. But often joining these groups will cut the fee down dramatically and would be worth considering.