Here are some websites I have found useful. Hope you do, too.  

www.bbc.co.uk/writersroom  The BBC Writers's Room. First port of call to check current opportunities at the Beeb.

www.channel4.com/4laughs  Gag & Cartoon competition/news/hints. State of the art web comedy.

www.newsrevue.com  Website for London's longest-running live topical sketch show.

www.itv.com/shootthewriters  Although currently "resting", this has been one of the best opportunities for new TV Sketch Writers

www.writing.org.uk  Excellent practical hints for TV and Screen writers.

www.chortle.co.uk  A major UK comedy site, the bible for standup comics.

www.showbusiness-success.com  Career coaching and encouragement for writers and performers in all fields.

www.funnywomen.co.uk  Website of organisation which promotes female standup comics and runs an annual competition.

www.writerswrite.com  Good allround writers' site.

www.deadbrain.co.uk  UK satire site. One of the few consistently funny topical websites.

www.scribblepad.co.uk   Useful site with tips for writers in all genres and styles