It can be a big waste of time for both you and the lawyer if you're not prepared for your first meeting. Being unprepared may also end up costing you money, because it will take longer for the lawyer you hire to get up to speed on your legal matter.
Don't be afraid to subtly quiz prospective lawyers to see if they really know what they are talking about. Maybe you could even ask them for definitions of a few IT terms to see if they can tell you what they mean.