Title says it all, I've tried wifi-hostapd-app but I always run into trouble while installing one of its dependencies, dnsmasq specifically. I read one of the workarounds is to disable Ubuntu's Network Manager, I'd rather not do that.
maybe this can help you to better deal with hostapd:
for gui you can check out this project (did not check myself but will sometimes :D):
... and ... tataaaa if you are using ubuntu (at least since version 11.10) recent versions of Ubuntu have an option in the Network Manager GUI to share one internet connection over a LAN or WLAN. enjoy! :D
There is nothing better than the CLI. Here is a little CLI program that easily setup an host AP with hostapd: create_ap.
It's made by an archlinux user, but it should work without problem on ubuntu 15.04, even 14.04 or 14.10 as long as all the needed depedancies are installed.
Note: I have not tested it on ubuntu, only in archlinux.