I'm planning to post at least once a day while I'm digging (July 1st to July 12th), but before/during/after that there are at least four other potential sources of daily info on the state of the Vindolanda excavations:
Daily tweets from Justin Blake, Deputy Director of Vindolanda Excavations, giving some official interpretation of the various trenches; these usually include a picture.
The Vindolanda Field School blog. Not necessarily every day, and includes their whole "summer in Northumberland" experience. Excavation updates are almost all from the North Field.
The official Vindolanda Trust Excavation Blog. Excellent weekly summary (usually posted on Friday) of the action by Justin Blake, occasional entries on other topics. Sometimes features video blogs that really make you feel like you are on a guided tour.
WeDigVindolanda Forum. Individual volunteers sometimes post reports and photos here. Also has an excellent historical overview of Vindolanda and description of typical finds. Need to join the forum to see everything.