I'm not saying it doesn't happen, but I haven't had any personal experience with anything of this sort throughout the whole time I have been here (in Northern Virginia).
If you go to Jim Webb's website you can listen to the voicemail that was left on a Dem voter's answering machine that threatened him with criminal charges if he showed up to vote. The man who left the voicemail said that the voter in question was determined to be registered in NY and was not eligible to vote in VA. The man actually has been registered in VA since 1998 and has voted in VA elections since 1998. He is considering legal action if the can find out who left the voter-supressing call on his machine.
Moral of the story is this is not some rumor cooked up by a partisan Democrat, this is actually happening.