You've got mail, lesson plans, in fact…
There are lots of places on the Web where you will find lesson plans — some of them with an email subscription service, a handy way of having things come to you, rather than having to go looking for them.
All of those listed below are free resources, though most require registration.
In alphabetical order, with [weekly], [monthly] or [none] indicating whether or not you can subscribe.
BBC "Words in the News" [none]
The BBC has a weekly lesson plan on a topical story with "notes and instructions for teachers, worksheets for students and a full answer key" — and the added advantage of an audio version of the same story.
Business English lesson plans [weekly]
MacMillan will send you a weekly Business English lesson plan — which you can register for and get the Inside Out lesson plan (see below) in the same mail. Further Business English lesson plans on OneStopEnglish (see below).
DevelopingTeachers.com [weekly tips], [monthly newsletter]
DevelopingTeachers has both weekly tips and an excellent monthly newsletter (ideas and activities (…) centred around a different subject (…) links to web sites for resource material" etc. Also a great archive of useful things, including lesson plans.
Inside Out [weekly]
Inside Out is a popular general English coursebook with a weekly "e-lesson".
OneStopEnglish [monthly update]
OneStopEnglish is an excellent website for English teachers, with stacks of resources, lesson plans and articles of interest, including an excellent lesson plan bank, with lessons at three different levels based on articles in The Guardian Weekly. The monthly update keeps you in touch with new content.
And not just lesson plans…
Humanising English Teaching [6 issues a year]
HLT is an online magazine — though in fact "online" means that you have to done load it. In your mailbox, you'll get only an alert that a new issue has come out. In your download, some very interesting articles…
TeachingEnglish.org.uk [monthly update]
The BBC / British Council TeachingEnglish.org.uk website is — like OneStopEnglish — one of the best: for lesson plans, articles, ideas, tips… Like OSE is has a monthly update to tell you about new things on the site. If you become an information junkie like myself and get into RSS, it also has a feed: you get updates by the minute, instead of by the month…!