The current backup procedure we using a tar command in linux.

The files are stored in one partition in different folders. The docs stores in day wise folders like ex: /usr/data/xyz/20050129, /usr/data/xyz/20050130 ………….etc
We using tar & gzip command to take backup everyday. The backup file ex: *_20050129.tar.gz and copying the file to backup server (remote m/c).
Everyday tar and zipping all files takes more time is it any way or other methods to take incremental backup?
Using shell script is it possible to take incremental backup everyday so that we can save time.
We are also open to suggestions on other backup methods.

Thanks in advance for your help in this regards.

Use a commercial product like Veritas NetBackup.
It can backup/archive. Pay $$ to solve your problem

rsync
Is an open source utility that provides fast incremental file transfer. rsync is freely available under the GPL.

rsync useage examples.
http://rsync.samba.org/examples.html

Why not run a cron command to
execute a backup command or a script?

You could do this at night when no one is
using computers.