I'll call, email is not good enough

Some of my closest friendships' predate the email/chat/Orkut/FB era. With those friends, email communication mostly meant spamming with fwds. And that feeling persists! Dropping them an email (or receiving one from them) seems so unfriendly. Its better to say - hey, couldn't reach your cell on your birthday, hence the delay in wishing you; instead of sending them a very thoughtful happy bday email on time.
But this feeling has to go. What with half of them in US, and half of them married off, I always end up getting the feeling - would I be disturbing him/her at this time of day/night?
After having missed so many birthdays now, heres a mental note - Email is atleast good enough to say - happy bday, will call u soon, and I have not forgotten its your birthday! :)