It can be really fun to watch the volcanic avtivity, thankfully there are numerus webcams on site and here we have collected a few of that that you can take a look at.
If the webcams are down or If visibility is bad you can view the tremor chart from the Icelandic Met office here (if the blue line goes above 4000 you can expect to see lava flow)
The Department of Civil Protection and Emergency Management has a few cameras that you can view here
The Met office has a couple of cameras that you can view here