Hero Skills

Really, the two best ways to get skills for Heroes is to play characters of those professions - preferably in Prophecies for the skill quests (hint: now that your E/N can change his secondary, go to the wiki and look up the skill quest lists - then go back to Ascalon and do the profession-specific quests scattered around, and then to Yak's Bend for the rest) and to start a character in Nightfall and talk to every single trainer in the area when going back to the Fields for the secondary profession at level 5 (and make sure to, at the start, check with all of the trainers for your primary profession - there's 2-3 for each profession).

After that, use your Hero Skill points (gained whenever one of your titles goes up - so you should have a few on your E/N since you've done EotN) at one of the heralds (that give you the mission/dungeon books) in EotN or at the [Hero Skills] trainers in Nightfall to unlock even more skills for your Heroes (and you, even if you're not currently that profession) to use. This is how I unlock my hero skills, because it allows your character to get those skills too, not just for your heroes or pvp.

The drawback is, this is the longer route than unlocking them using Balthazar Factions since you have to build characters.

As suggested, skills unlocked in pvp can be used by heroes. A quick way to unlock all the skills for heroes and pvp is to buy the skill packs, lazy I know, but it gets your heroes up and running in no time. It will not unlock the skills for your pve player characters though. Actually, the unlock packs DO unlock the skills for PvE characters. But, the packs don't TEACH the skills. There is a difference. The advantage for players is that all unlocked skills for a campaign are immediately available from any trainer in that campaign, so you can buy skills from early trainers that you would otherwise have to wait to get until reaching areas near the endgame.