LinuxQuestions.org - extending ext3 lvm

I have a quick question. I am using LVM on one of my hds and have mounted several of my partitions to the logical volumes in my vg. They are all formated as ext3 partitions. The other day I decided to try extending one of my partitions without really looking into the details. I used lvextend but according to df I have not done anything to that partition yet. While surfing, I have noticed that people use resize2fs to deal with ext2 but can I use this with ext3? The partition that I happened to try to resize is /usr. That doesnt matter too much accept that if I mess something up my system really is screwed. Anyway if I can use resize2fs, it would by nice to have someone tell me the proper steps to get the correct size recognized by my system.

Thanks!