Basically, the league year ends on June 15 & the next one begins June 16.
Teams announce their end-of-season rosters, which are largely procedural. What's interesting is to see if someone was under contract and left off the roster, as that player becomes a UFA. They'll also announce protected lists, which are again procedural, but allow a team to protect someone who was on the roster the year before or the start of the year and finished the season in a different league. Teams have the exclusive ECHL right to sign any player from their own protected list until June 30.
All players from Quad City's roster are UFAs.
The *really* important one to follow is when the teams announce their qualified offer lists - teams are allowed to give qualifying offers to up to eight players, and the team retains the rights for up to one year (non-vets) or Aug. 1 (vets) to that player. Teams may sign others who do not count against that eight-player "protected" limit (but not necessarily announce the signings - I know some teams like to spread signing announcements out and release one or two a week, so there's constant news over the summer).
If you're a Newfoundland or Maine fan, keep an eye on college FAs, as well as players not protected from other teams.