There is a large number of accommodation options in the historical centre of the city of Lecce. You can use websites like booking.com and airbnb.com to book something suitable. Lecce sees a lot of tourism in the summer so book your accommodation as early as possible!
You can also use the following list of hotels. Some of them offer special discounts for OECS18 participants. Just let them know by email or phone that you are attending OECS18 unless otherwise noted below.