I will be making a business trip out to California and thought that I might take a couple of days and drive over to Yosemite. since I have never been before. But I will only have a day or a day and a half to see the park. Any reccomendations on the must see things in the park? What can I fit into this timespan? Best place to stay for convenience?

You didn't say when you'll be making the trip. If it's soon, you'll having trouble finding a place to stay. You also don't say where you'll be coming from. For that short amount of time, you might consider taking a tour from there.
If you provide more details, you'll get better info.

You can tour the Yosemite valley in a day or two. The park service offers many tour options in wonderful open air trams. There are shuttle buses that drop you off at the major attractions for you to explore on your own.
Try to stay at one of the park lodges in the Valley- the Yosemite Lodge or Awhanee. Call asap for reservations, lodging is tight, you could get a cancellation. Try to get up to Glacier point, walk out to Lower Yosemite falls, take binoculars to watch the climbers, eat dinner at the Awhanee, it is a wonderful park to visit.

WHEN is your trip? There are no accomodations (except rare cancellations) in the Valley or nearby until mid/late September. In fact the Ahwahnee is essentially booked solid for the rest of the year because it is celebrating its 75th anniversary and has a lot of special events.

Let us know when you'll be out here and then maybe we can give you some ideas.

I have a business trip to Sacramento in late September and another one probably next April. I really hadn't decided which trip I would add the Yosemite trip to. I thought that either one, that I could fly in on Friday night or Saturday morning and use the weekend to see Yosemite

Definitely April -

Because you will be able to get a room, but mostly because the waterfalls will be at full force. In Sept most are almost dry.

Definitely go in April for the reasons just stated.

If you have the choice, I agree with everyone else and go in April!

You will want to spend your time in Yosemite Valley.

Utahtea

I have to disagree about the difficulty of getting a place to stay in the valley. Within a week of my trip this July, I was able to get my choice of rooms at the Yosemite Lodge simply by using the reservations area of the website. When I was checking in, there were a couple of people who were able to get walk-up reservations for that night with no problem. Now this was during the week but it was the week of the 4th of July and the park was quite crowded.

My understanding is that there are MANY cancellations so if you are patient you can usually get what you want.

We were also able to get last minute reservations (within a week) in June inside the park - almost every type of accomodation was available from the Ahwahnee to tent cabins. The cancellation deadline for in park reservations is 72 hours in advance for most properties. If your plans are flexible, this might work for you.

Does anyone know when glacier point road opens for the season? This would be my only reservation about going in April - the view is spectacular from up here and you wouldn't want to miss it.