I have three, so far. There is 3 years (almost exactly) between the first and second and a mere 19 months between #2 and #3. #2 is exteremly high maintance and was a very sick infant. I was terrified when I found out I was pregnant again. However, he was so young, he never missed a beat. There was no "adjustment". I'm hoping for another 1 - 1/2 year age difference.
Now when I had my first, we did a lot to prepare him. Books galore. The one I love the most is What to expect when mommy is pregnant and What to expect when the new baby comes home. There were many others too that were just stories. The Seasame Street video Three Bears & a Baby is also good.
Just remember to still make one on one time with older children. It is much more important than laundry. A walk around the block, 15 minutes at the local park, an ice cream treat once a month is all that takes. Then if you nurse, use that time to do quiet activities (reading, board games) with younger children. If you bottle feed (or pump) let the older one help with feeding. And let them help with diaper changes (getting the diaper, throwing the dirty one in the trash/diaper container). Let them make faces and talk to baby when your doing something else (close by). My oldest loved to burp #2 when they were little. They were also told what great teachers they were to the younger siblings. And then we catch them being good & helpful as much as possible. We also tried not to disrupt their normal routines & let them bring treats to preschool for celebration (ask teachers first!). We also refer to the new baby as "our baby".
Before the new baby was born, we always had our older children help pick out things for the baby (coming home outfit, new blanket/toy) and take it to they baby when they came to visit at the hospital. Amazingly enough, the new baby also got the big sibling(s) a gift also. And so did mom & dad. Last time it was "Big Brother" t-shirts from Mom & Dad and Build-a-Bear gift certificates from baby (also a great diversion for when mommy wasn't around).
We had people tell us not to let the littler one visit in the hospital or don't let him see us with the new baby if he did visit. I totally ignored that advice. I figured it would be better to let him see us with that new baby right away so when we got home it wasn't a complete culture shock. And I am very glad I did. It was by far the best thing we could have done. It was a little difficult in the hospital, but when we got home, he had already experienced it and it wasn't a hard adjustment. Not to mention the extra time to process the idea. I had a bit of time in the hospital since my first two were emergency c-sections and my third a planned c-section (after the previous two, no choice).
Oh--on the c-sections. My older kids didn't understand why I couldn't hold them when standing. We made up for it with lots of sitting snuggle time. And after the 2nd, I ended up showing my oldest the incision, something I was trying desperately to shield him from for fear of frightening him. After he saw it, he was OK with it all. It didn't scare him at all, but helped him deal with my limitations the first few weeks.
The hardest thing about the second is learning to balance their needs when they both NEED you at the same time. But it only takes a short time. And to tell you the truth, I didn't notice any difference between 2 and 3. I don't even think it is that hard to run errands with 3 v. 1--just use the stroller (or those wonderful race car shopping carts at HEB grocery stores!--it's a smaller cart were the older two ride in the front & the baby is in the normal spot. Not like those awful things
Walmart has with the big double blue seats that are impossible to push and get around the isles with).
If you are worried about will I have enough love, don't be. Do you love your parents/siblings any less once you met your husband? Your you DH any less after having a baby? There is an infinite amount of love to go around. The more kids you have, the more love multiplies. Although, I do have to admit that I didn't think I loved my 2nd as much as my first. I was horrified at my feelings after his birth. I had post partum depression though. Luckily some people noticed it and I got help with those issues. Once the ppd was gone, all that love was there and bubbling over. SO, if you think you don't love the 2nd as much, talk to your dr. about ppd!!
I wouldn't worry about having a second. A sibling is one of the best gifts you can give a child. Someone to share the same experiences and memories. Someone to keep in contact with as life goes on into adulthood and old age. Someone to share the joys and heartaches in life in a way no other person can because you come from the same place, no matter how different you are in every other way. And do remember, all kids are different people.
This is way too long, so GOOD LUCK!!
My oldest DD was 3 when #4 was born
You will do great! Just enjoy every minute and have a sense of humor. It is so much fun! 
i clearly remember ds crying one night as he awaited feeding, dd shouts out from her bed "baby, will you never learn to be quiet and just sleep?!" 
).
I think 3 years is a great age difference b/c you will get some alone time with #2 while #1 is at school - 
