This time I am here with few of the sites which I know from where you can send free sms or get free sms reminders for any future event,Well there are a lot of it..,But to start with here is: : From here you can send two-four sms daily without registering and upto 160 characters!

Way2SMS: Here you need to register before sending.but you can send unlimited sms to anyone, the sender will receive your number and a small ad at bottom..

160by2 : This is same as way2sms, but more preferable by me coz, its really simple and shockingly fast! As the name says in 160 characters 80 will be our sms and 80 will be the ad part!
Here you can also set your time to send sms at future time or any reminder...

Postitsms : It is one more where you can set reminder for any future dates..
This is awesome,tried by me, as it sends the alert exactly at the time set! : Send unlimited free sms with your desired name in the sender field!!
This is one of the most used by me,I also urge to try this once..This is my favorite!!