Assuming your computer has no video in ports then (most don't but some older ones might have if you're lucky)
Buy a cheap dongle that will do it, it'll come with software and you can record it onto the computer then edit (triim, crop etc either in that program or others). If you're even luckier you can use any software, often it seems you are locked into the one that came with it (I've tried a few years back)
I still regularly use mine at work (old science education videos)
One warning though, by default the video will wobble around slightly unless you VHS play has quality stability chips in them. Mine doesn't and I just crop the edges of on encode and live with it. You can use other software to have a go but it's very time consuming.
or use other such dedicated equipment.
Random link to something that'll do the job
http://www.maximumpc.com/article/news/b ... verter_yet
that sort of thing.